Clinical Practice & Epidemiology in Mental Health




ISSN: 1745-0179 ― Volume 14, 2018
REVIEW ARTICLE

The Prevalence of Autism Spectrum Disorders in Adult Psychiatric Inpatients: A Systematic Review



Samuel Tromans1, 2, *, Verity Chester3, 4, Reza Kiani1, 2, Regi Alexander1, 5, Terry Brugha1, 2
1 Department of Health Sciences, University of Leicester, Leicester, Leicestershire, United Kingdom
2 Leicestershire Partnership NHS Trust, Leicester, Leicestershire, United Kingdom
3 Priory Group, Norwich, Norfolk, United Kingdom
4 Norwich Medical School, University of East Anglia, Norwich, United Kingdom
5 Hertfordshire Partnership University NHS Foundation Trust, Broadland Clinic & Astley Court, Norwich, United Kingdom

Abstract

Background:

Whilst the prevalence of autism spectrum disorders in adults within the community setting is well-established, less is known about the prevalence among adults based within a psychiatric inpatient setting.

Objective:

To conduct a systematic literature review pertaining to the prevalence of autism spectrum disorders among the adult psychiatric inpatient population.

Method:

Eligibility criteria included: (a) investigation of the prevalence of autism spectrum disorders (b) adult psychiatric inpatient study population (c) published in English language. Electronic databases accessed included PubMed, Medline, CINAHL, PsycINFO and EMBASE. Additionally, the ancestry method was utilised for the references of eligible papers, as well as grey literature searches and consultation with experts in the field.

Results:

From the search, 4 studies were identified which satisfied the inclusion criteria, conducted in a variety of inpatient psychiatric settings, including secure forensic and intellectual disability units and a state psychiatric hospital. There were significant differences in methodological approaches, including the screening tests, diagnostic instruments and diagnostic criteria utilised. Autism spectrum disorder prevalence estimates varied considerably, from 2.4-9.9%.

Conclusion:

From the limited research data currently available, it appears that the prevalence of autism spectrum disorders is increased in inpatient psychiatric settings relative to the general population. There is a need for further high quality research in this patient group, to add to this limited evidence base, as well as in developing effective strategies to identify patients with a high likelihood of autism spectrum disorders within this setting.

Keywords: Autism, Asperger, Psychiatric, Inpatient, Intellectual, Disability, Adult.


Article Information


Identifiers and Pagination:

Year: 2018
Volume: 14
First Page: 177
Last Page: 187
Publisher Id: CPEMH-14-177
DOI: 10.2174/1745017901814010177

Article History:

Received Date: 25/04/2018
Revision Received Date: 22/5/2018
Acceptance Date: 16/06/2018
Electronic publication date: 29/08/2018
Collection year: 2018

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© 2018 Tromans et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


* Address correspondence to this author at the Department of Health Sciences, University of Leicester, Leicester, Leicestershire, United Kingdom; Tel: 0116 295 5098; E-mail: sjt56@leicester.ac.uk




1. INTRODUCTION

Autism Spectrum Disorders (ASD) describe a range of neurodevelopmental disorders characterised by difficulties in social interaction and communication, as well as restricted, stereotyped and repetitive behaviours [1The ICD-10 classification of mental and behavioural disorders: clinical descriptions and diagnostic guidelines 1992.]. ASD subtypes include autism, Asperger’s Syndrome (AS) and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS); a further two PDD’s exist (Rett’s syndrome and childhood disintegrative disorder), though these are qualitatively distinct from the aforementioned subtypes, and are thus not considered further in this review [2Witwer AN, Lecavalier L. Examining the validity of autism spectrum disorder subtypes. J Autism Dev Disord 2008; 38(9): 1611-24.[http://dx.doi.org/10.1007/s10803-008-0541-2] [PMID: 18327636] ]. Though originating in childhood, the debilitating effects of ASD persist into later life, leading to many individuals requiring high levels of support throughout their adult life [3Howlin P, Goode S, Hutton J, Rutter M. Adult outcome for children with autism. J Child Psychol Psychiatry 2004; 45(2): 212-29.[http://dx.doi.org/10.1111/j.1469-7610.2004.00215.x] [PMID: 14982237] ]. Indeed, whilst most research has historically focussed on ASD in children, in recent years there has been an increasing focus on the clinical needs of adult patients [4Lai MC, Baron-Cohen S. Identifying the lost generation of adults with autism spectrum conditions. Lancet Psychiatry 2015; 2(11): 1013-27.[http://dx.doi.org/10.1016/S2215-0366(15)00277-1] [PMID: 26544750] ]. Despite this, service provision for adults with ASD is still in its relative infancy [5Murphy CM, Wilson CE, Robertson DM, et al. Autism spectrum disorder in adults: diagnosis, management, and health services development. Neuropsychiatr Dis Treat 2016; 12: 1669-86.[http://dx.doi.org/10.2147/NDT.S65455] [PMID: 27462160] ]. An important component of this is ready access to diagnostic services for adults with suspected ASD, as diagnosis is essential in both understanding their needs and planning their subsequent care [6Garland J, O’Rourke L, Robertson D. Autism spectrum disorder in adults: Clinical features and the role of the psychiatrist. Adv Psychiatr Treat 2013; 19(5): 378-91.[http://dx.doi.org/10.1192/apt.bp.112.010439] ].

Community-based prevalence rates for autism in the general population show considerable variation across studies, though recent systematic reviews and large-scale epidemiological research estimate rates of between 0.7-1.1% [7Baxter AJ, Brugha TS, Erskine HE, Scheurer RW, Vos T, Scott JG. The epidemiology and global burden of autism spectrum disorders. Psychol Med 2015; 45(3): 601-13.[http://dx.doi.org/10.1017/S003329171400172X] [PMID: 25108395] , 8Brugha TS, Spiers N, Bankart J, et al. Epidemiology of autism in adults across age groups and ability levels. Br J Psychiatry 2016; 209(6): 498-503.[http://dx.doi.org/10.1192/bjp.bp.115.174649] [PMID: 27388569] ]. Additionally, the prevalence of autism is significantly higher in people with moderate to profound intellectual disability (ID); Brugha et al. [8Brugha TS, Spiers N, Bankart J, et al. Epidemiology of autism in adults across age groups and ability levels. Br J Psychiatry 2016; 209(6): 498-503.[http://dx.doi.org/10.1192/bjp.bp.115.174649] [PMID: 27388569] ] found a prevalence of 39.3% (95% confidence interval 31.0-48.4) for this patient group, compared to 1.0% (95% confidence interval 0.4-2.2) for those with mild ID. For these reasons, ASD represents a major global public health issue, responsible for over 111 Disability Adjusted Life Years (DALY’s) per 100,000 persons [7Baxter AJ, Brugha TS, Erskine HE, Scheurer RW, Vos T, Scott JG. The epidemiology and global burden of autism spectrum disorders. Psychol Med 2015; 45(3): 601-13.[http://dx.doi.org/10.1017/S003329171400172X] [PMID: 25108395] ].

However, while there has been a focus on the prevalence of ASD in the community, its prevalence within an inpatient psychiatric setting is less well established. Mandell et al. [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] ] (2012) cited several reasons to support the suggestion that ASD may be overrepresented and underdiagnosed among adults within such a setting, including a lack of training among adult psychiatrists in conditions originating in childhood. Additionally, presence of comorbid psychiatric disorders that are more common in people with ASD could potentially complicate the diagnostic picture [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] , 10Gillberg C, Billstedt E. Autism and Asperger syndrome: coexistence with other clinical disorders. Acta Psychiatr Scand 2000; 102(5): 321-30.[http://dx.doi.org/10.1034/j.1600-0447.2000.102005321.x] [PMID: 11098802] ], including depression [11Hofvander B, Delorme R, Chaste P, et al. Psychiatric and psychosocial problems in adults with normal-intelligence autism spectrum disorders. BMC Psychiatry 2009; 9(1): 35.[http://dx.doi.org/10.1186/1471-244X-9-35] [PMID: 19515234] , 12Ghaziuddin M, Ghaziuddin N, Greden J. Depression in persons with autism: implications for research and clinical care. J Autism Dev Disord 2002; 32(4): 299-306.[http://dx.doi.org/10.1023/A:1016330802348] [PMID: 12199134] ], bipolar disorder [13Croen LA, Zerbo O, Qian Y, et al. The health status of adults on the autism spectrum. Autism 2015; 19(7): 814-23.[http://dx.doi.org/10.1177/1362361315577517] [PMID: 25911091] ], anxiety disorders [14Mazzone L, Ruta L, Reale L. Psychiatric comorbidities in asperger syndrome and high functioning autism: diagnostic challenges. Ann Gen Psychiatry 2012; 11(1): 16.[http://dx.doi.org/10.1186/1744-859X-11-16] [PMID: 22731684] ], schizophrenia [13Croen LA, Zerbo O, Qian Y, et al. The health status of adults on the autism spectrum. Autism 2015; 19(7): 814-23.[http://dx.doi.org/10.1177/1362361315577517] [PMID: 25911091] , 15Larson FV, Wagner AP, Jones PB, et al. Psychosis in autism: Comparison of the features of both conditions in a dually affected cohort. Br J Psychiatry 2017; 210(4): 269-75.[http://dx.doi.org/10.1192/bjp.bp.116.187682] [PMID: 27979819] ], attention deficit hyperactivity disorder [11Hofvander B, Delorme R, Chaste P, et al. Psychiatric and psychosocial problems in adults with normal-intelligence autism spectrum disorders. BMC Psychiatry 2009; 9(1): 35.[http://dx.doi.org/10.1186/1471-244X-9-35] [PMID: 19515234] , 14Mazzone L, Ruta L, Reale L. Psychiatric comorbidities in asperger syndrome and high functioning autism: diagnostic challenges. Ann Gen Psychiatry 2012; 11(1): 16.[http://dx.doi.org/10.1186/1744-859X-11-16] [PMID: 22731684] ], alcohol and substance abuse [13Croen LA, Zerbo O, Qian Y, et al. The health status of adults on the autism spectrum. Autism 2015; 19(7): 814-23.[http://dx.doi.org/10.1177/1362361315577517] [PMID: 25911091] ], as well as ID [16Strømme P, Diseth TH. Prevalence of psychiatric diagnoses in children with mental retardation: Data from a population-based study. Dev Med Child Neurol 2000; 42(4): 266-70.[http://dx.doi.org/10.1017/S0012162200000451] [PMID: 10795566] , 17Emerson E, Baines S. The estimated prevalence of autism among adults with learning disabilities in England 2010.]. Such conditions could lead to instances of failure to identify ASD where present, as well as misattribution of ASD symptoms to other forms of mental disorder, such as schizophrenia [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] , 15Larson FV, Wagner AP, Jones PB, et al. Psychosis in autism: Comparison of the features of both conditions in a dually affected cohort. Br J Psychiatry 2017; 210(4): 269-75.[http://dx.doi.org/10.1192/bjp.bp.116.187682] [PMID: 27979819] ]. Finally, the diagnostic criteria for ASD have broadened in recent decades, in contrast to the narrowing of those for schizophrenia [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] , 18 American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 5th edn (DSM-5). Arlington: American Psychiatric Publishing 2013.-20American Psychiatric Association Diagnostic and statistical manual of mental disorders, 4th edn (DSM-IV) Washington: American Psychiatric Association 1994 ].

Understanding the prevalence of ASD within an inpatient psychiatric setting has significant implications for resource allocation by healthcare providers, as this patient group could potentially represent a target for case identification. Identifying individuals with ASD will ensure that the clinical needs of such individuals are better understood, and taken into account in any subsequent treatment approach [15Larson FV, Wagner AP, Jones PB, et al. Psychosis in autism: Comparison of the features of both conditions in a dually affected cohort. Br J Psychiatry 2017; 210(4): 269-75.[http://dx.doi.org/10.1192/bjp.bp.116.187682] [PMID: 27979819] ]. This could potentially lead to improved therapeutic outcomes in both the shorter (e.g reduced length of hospital stay) and longer terms (e.g reduced likelihood of readmission).

The purpose of this systematic review was to evaluate the current evidence pertaining to the prevalence of ASD in adults within an inpatient psychiatric setting. This is the first systematic review on this topic.

2. MATERIALS AND METHODS

2.1. Systematic Search Strategy

The PubMed, MedLine, CINAHL, PsycINFO and EMBASE databases were searched from their respective inceptions to 10th December 2017. Titles and abstracts were searched for the following terms: (((autism spectrum disorders OR autis* OR Asperger* OR PDD OR PDDs OR PDD-NOS OR ASD OR ASDs OR pervasive development* disorder* OR Kanner*))) AND (((prevalen* OR screen* OR rate*))) AND (((adult))). Please note that autis* was used as a search term to cover titles and abstracts containing either ‘autism’ or ‘autistic’; prevalen* was used as a search term to cover titles and abstracts containing either ‘prevalence’ or ‘prevalent’. All titles and abstracts of articles that remained following removal of duplicates were screened against the inclusion criteria by two investigators (ST + VC). If they were considered to potentially satisfy inclusion criteria, full texts were accessed. In instances where there was uncertainty between ST and VC regarding the eligibility of an article, the final decision was made by RK. The ancestry method was utilised to identify additional studies within the references of eligible papers. Grey literature searches included Google Scholar and manual searches. Experts in the field were consulted to identify any additional published or unpublished data; for all articles identified via expert consultation, the full texts of the articles were assessed. Two separate searches were conducted by the local research design and library services, to find studies not identified by the above methods. The details of the search were registered on the PROSPERO database (Registration No. CRD42017084616).

2.2. Study Selection

Studies were included provided they satisfied all of the following criteria: (a) investigation of the prevalence of autism spectrum disorders within a psychiatric inpatient population (b) adult patients (≥ 16 years of age) (c) published in English language. Please note that a basic requirement for ‘investigation of the prevalence of autism spectrum disorders’ was that all participants within the study population were subjected to some form of autism-specific testing. Several studies were identified which simply reported the proportions of inpatients whom were identified as having autism through routine clinical practice; for the purposes of this review, these were not considered true prevalence studies and were excluded accordingly. Such studies would likely underestimate prevalence, as the diagnostic possibility of autism is not being proactively assessed using relevant assessment tools in all individuals within the study population.

2.3. Data Extraction

For each article, data was extracted pertaining to the year and location of the study, as well as the number of individuals enrolled, screened (where applicable) and undergoing full diagnostic assessment. The methods employed for such assessments were also obtained, as well as the ASD diagnostic criteria used. Where available, information was also extracted regarding the individuals included as well as excluded from the study, as this would impact on the generalisability of any resultant prevalence estimate. The proportion of male patients was also documented, as to determine whether the study proportion disproportionately represented one gender over another.

2.4. Data Synthesis

The prevalence results obtained were considered both with regard to overall findings for ASD prevalence across available studies, as well as specifically within ID, non-ID and forensic subgroups.

2.5. Quality Assessment

All articles that qualified for inclusion were stored by one investigator (ST) according to the 22-item STROBE checklist of cross-sectional studies [21Vandenbroucke JP, von Elm E, Altman DG, et al. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): explanation and elaboration. PLoS Med 2007; 4(10): e297.[http://dx.doi.org/10.1371/journal.pmed.0040297] [PMID: 17941715] ], as all studies were of this type. No studies qualifying for inclusion were excluded based upon their STROBE score.

3. RESULTS

3.1. Study Characteristics

Database searches were conducted on 10th December 2017. The database search yielded a total of n=7463 articles, including n=2885 articles in PubMed, n=1199 articles in MedLine, n=296 articles in CINAHL, n=1045 articles in PsycINFO and n=2038 articles in EMBASE. A total of n=80 additional records were identified through other techniques (ancestry method, grey literature searches and expert consultation). Following removal of duplicates, n=4237 articles remained for screening. Fig. (1) illustrates a PRISMA flow chart summary of the systematic search.

Upon abstract screening, a further 4126 articles were excluded for a variety of reasons, including focusing on research topics unrelated to Autism Spectrum Disorder (such as Atrial Septal Defect), failing to satisfy the search criteria (e.g studies on child populations, not measuring prevalence of Autism etc.), or not being published in English language. Thus, full texts of 111 articles were assessed, of which 4 qualified for inclusion. Of the included papers, 3 were identified on the initial database search, and 1 via the ancestry method. Grey literature searches and liaison with experts failed to identify any additional studies satisfying inclusion criteria.

3.2. Findings of Included Studies

Table 1 summarises the details of all four included studies. Publication dates for such studies ranged from 1982 to 2012, and all were conducted in England or North America. The characteristics of the study samples varied markedly, including both state [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] ] and secure psychiatric hospitals [22Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327] , 23Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.], as well as long-stay treatment facilities for individuals with ID [24Shah A, Holmes N, Wing L. Prevalence of autism and related conditions in adults in a mental handicap hospital. Appl Res Ment Retard 1982; 3(3): 303-17.[http://dx.doi.org/10.1016/0270-3092(82)90022-4] [PMID: 7149707] ]. Limited data were available on the mean age for many included studies (though all were conducted on adult populations), with mean age ranging from 42 to 52 years. For all included studies, the majority of the study population comprised of males, though this varied considerably from 61-100%. All included studies were found via the database searching process, with the exception of Hare et al. [23Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.], identified through the ancestry method. No additional eligible articles were identified through either grey literature searches or consultation with experts in the field.

Fig. (1)
PRISMA flow diagram of systematic search [25Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 2009; 6(7): e1000097.[http://dx.doi.org/10.1371/journal.pmed.1000097] [PMID: 19621072] ].


Table 1
Summary of included studies.


All but one of the included studies estimated the prevalence of ASD in general, though the methods of diagnosis varied considerably, from review of existing case notes, to using more standardised tools, such as the Disability Assessment Schedule (DAS) [32Holmes N, Shah A, Wing L. The Disability Assessment Schedule: A brief screening device for use with the mentally retarded. Psychol Med 1982; 12(4): 879-90.[http://dx.doi.org/10.1017/S0033291700049175] [PMID: 7156257] ], Handicaps, Behaviours and Skills Schedule (HBS) [27Wing L. The MRC handicaps, behaviour & skills (HBS) schedule. Acta Psychiatr Scand 1980; 62(S285): 241-8.[http://dx.doi.org/10.1111/j.1600-0447.1980.tb07696.x] ], and the Diagnostic Interview for Genetics Studies (DIGS) [29Nurnberger JI Jr, Blehar MC, Kaufmann CA, et al. Diagnostic interview for genetic studies. Rationale, unique features, and training. Arch Gen Psychiatry 1994; 51(11): 849-59.[http://dx.doi.org/10.1001/archpsyc.1994.03950110009002] [PMID: 7944874] ] and Autism Diagnostic Inventory-Revised (ADI-R) [30Lord C, Rutter M, Le Couteur A. Autism Diagnostic Interview-Revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. J Autism Dev Disord 1994; 24(5): 659-85.[http://dx.doi.org/10.1007/BF02172145] [PMID: 7814313] ]. In contrast, Scragg and Shah [22Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327] ] estimated the prevalence of AS only, rather than all subtypes of ASD.

Prevalence estimates for ASD ranged from 4 to 9.9%, with Scragg and Shah [22Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327] ] estimating a prevalence of 1.5% (or 2.3% when equivocal cases are included) for AS only.

3.3. Subgroup Analyses

Shah et al. [24Shah A, Holmes N, Wing L. Prevalence of autism and related conditions in adults in a mental handicap hospital. Appl Res Ment Retard 1982; 3(3): 303-17.[http://dx.doi.org/10.1016/0270-3092(82)90022-4] [PMID: 7149707] ], the only eligible study where the entire study population had ID, provided an ASD prevalence estimate of 4%. Mandell et al. [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] ] provided an estimate of 19.6% from the subgroup of patients in their study whom had ID.

Two studies involved a mixture of ID and non-ID individuals. Mandell et al. [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] ] estimated an overall ASD prevalence of 9.9% whereas Hare et al. [23Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.] estimated 2.4%, increased to 4.8% when equivocal cases were taken into account.

Though none of the studies were conducted on non-ID patients only, Mandell et al. [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] ] provided prevalence data pertaining to the non-ID subgroup of their study population, which yielded a prevalence estimate of 5.3%.

It is important to note that Scragg and Shah [22Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327] ] do not discuss the ID status of their study population in general, only providing details that none of the individuals diagnosed with AS had ID. The aforementioned studies conducted by Hare et al. [23Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.] and Scragg and Shah [22Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327] ] were both based in forensic settings.

3.4. Qualitative Summary of Relevant Excluded Studies

A brief report by Ferriter et al. [33Ferriter M, Hare D, Bendall P, et al. Brief report: Assessment of a screening tool for autistic spectrum disorders in adult population. J Autism Dev Disord 2001; 31(3): 351-3.[http://dx.doi.org/10.1023/A:1010755505774] [PMID: 11518488] ] was excluded as it represented a summary of the same data covered in the more comprehensive eligible article by Hare et al. [23Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.], with additional evaluation of the interrater reliability of the ASDASQ screening tool [26Nylander L, Gillberg C. Screening for autism spectrum disorders in adult psychiatric out-patients: A preliminary report. Acta Psychiatr Scand 2001; 103(6): 428-34.[http://dx.doi.org/10.1034/j.1600-0447.2001.00175.x] [PMID: 11401656] ].

A study conducted by Turygin et al. [34Turygin N, Matson JL, Adams H. Prevalence of co-occurring disorders in a sample of adults with mild and moderate intellectual disabilities who reside in a residential treatment setting. Res Dev Disabil 2014; 35(7): 1802-8.[http://dx.doi.org/10.1016/j.ridd.2014.01.027] [PMID: 24656808] ] was excluded due to the study population not being subjected to some form of autism-specific testing, and rather the prevalence estimate of 9.9% (for a population of patients with ID within a residential treatment facility) being based on case note review and routine clinical assessment alone. There were several other studies excluded for this reason, such as Esan et al. [35Esan F, Chester V, Gunaratna IJ, Hoare S, Alexander RT. The clinical, forensic and treatment outcome factors of patients with autism spectrum disorder treated in a forensic intellectual disability service. J Appl Res Intellect Disabil 2015; 28(3): 193-200.[http://dx.doi.org/10.1111/jar.12121] [PMID: 25379816] ], Gustafsson [36Gustafsson C. The prevalence of people with intellectual disability admitted to general hospital psychiatric units: level of handicap, psychiatric diagnoses and care utilization. J Intellect Disabil Res 1997; 41(Pt 6): 519-26.[http://dx.doi.org/10.1111/j.1365-2788.1997.tb00745.x] [PMID: 9430057] ], and Lyall and Kelly [37Lyall R, Kelly M. Specialist psychiatric beds for people with learning disability. Psychiatr Bull 2007; 31(8): 297-300.[http://dx.doi.org/10.1192/pb.bp.106.011700] ], among others, further detailed in the supportive/supplementary material.

An article by Heinrich et al. [38Heinrich M, Böhm J, Sappok T. Diagnosing Autism in Adults with Intellectual Disability: Validation of the DiBAS-R in an Independent Sample. J Autism Dev Disord 2018; 48(2): 341-50.[http://dx.doi.org/10.1007/s10803-017-3336-5] [PMID: 28988347] ] was not included due to the study population excluding patients whom had previously been assessed for ASD, as well as the patients representing a mix of inpatients and community-based individuals. Their study involved diagnostic assessment of 381 adults with ID (220 male) according to ICD-10 criteria. Diagnostic decisions were made as part of a multidisciplinary case conference involving review of all available diagnostic information obtained via standardised ASD tools, including the ADI-R [30Lord C, Rutter M, Le Couteur A. Autism Diagnostic Interview-Revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. J Autism Dev Disord 1994; 24(5): 659-85.[http://dx.doi.org/10.1007/BF02172145] [PMID: 7814313] ], Autism Checklist (ACL) [39Sappok T, Heinrich M, Diefenbacher A. Psychometrische Eigenschaften der Autismus-Checkliste (ACL) für erwachsene Menschen mit Intelligenzminderung. Psychiatr Prax 2014; 41(1): 37-44.[PMID: 23681789] ], Autism Diagnostic Observation Schedule (ADOS) [40Lord C, Risi S, Lambrecht L, et al. The autism diagnostic observation schedule-generic: A standard measure of social and communication deficits associated with the spectrum of autism. J Autism Dev Disord 2000; 30(3): 205-23.[http://dx.doi.org/10.1023/A:1005592401947] [PMID: 11055457] ], scale of Pervasive Developmental Disorder in Mentally Retarded Persons (PDD-MRS) [41Kraijer D, de Bildt A. The PDD-MRS: An instrument for identification of autism spectrum disorders in persons with mental retardation. J Autism Dev Disord 2005; 35(4): 499-513.[http://dx.doi.org/10.1007/s10803-005-5040-0] [PMID: 16134035] ] and Music-based Autism Diagnostics (MUSAD) [42Bergmann T, Sappok T, Diefenbacher A, et al. Music-based Autism Diagnostics (MUSAD) - A newly developed diagnostic measure for adults with intellectual developmental disabilities suspected of autism. Res Dev Disabil 2015; 43-44: 123-35.[http://dx.doi.org/10.1016/j.ridd.2015.05.011] [PMID: 26183337] ]. A total of 92 patients (24.1% of the study population) were subsequently diagnosed with ASD.

The most frequent rationales for rejection of the remaining excluded articles for which full text assessments were undertaken included the study population being based in the community setting, the article reporting purely the proportion of autistic patients identified through routine clinical practice, the article representing a review rather than primary research, and the study population being comprised of people with strongly suspected or previously diagnosed autism. For further details pertaining to excluded studies, as well as the rationale for exclusion of all studies undergoing assessment of their full texts, please refer to the supportive/supplementary material.

4. DISCUSSION

In this systematic review we aimed to assess the current evidence relating to the prevalence of ASD among adults within inpatient psychiatric settings. There was a relative dearth of eligible studies, supporting the assertion that there is a need for further high quality research in order to provide more definitive evidence regarding the prevalence of ASD in inpatient psychiatric settings.

From this pool of eligible studies, we found wide ranging prevalence estimates, though there appears to be a general trend suggesting ASD is more prevalent in inpatient psychiatric settings relative to community populations. The reasons for such variance in estimates are likely manifold, as there is significant heterogeneity among the eligible studies, in terms of the characteristics of the patient populations studied, the study design, as well as the assessment tools and diagnostic criteria used.

With respect to study populations, it is essential that in studies involving a mixture of ID and non-ID patients, separate prevalence estimates are made, given the sizeable disparity in ASD prevalence estimates between this groups in community-based prevalence studies [7Baxter AJ, Brugha TS, Erskine HE, Scheurer RW, Vos T, Scott JG. The epidemiology and global burden of autism spectrum disorders. Psychol Med 2015; 45(3): 601-13.[http://dx.doi.org/10.1017/S003329171400172X] [PMID: 25108395] , 8Brugha TS, Spiers N, Bankart J, et al. Epidemiology of autism in adults across age groups and ability levels. Br J Psychiatry 2016; 209(6): 498-503.[http://dx.doi.org/10.1192/bjp.bp.115.174649] [PMID: 27388569] , 4Lai MC, Baron-Cohen S. Identifying the lost generation of adults with autism spectrum conditions. Lancet Psychiatry 2015; 2(11): 1013-27.[http://dx.doi.org/10.1016/S2215-0366(15)00277-1] [PMID: 26544750] , 3Howlin P, Goode S, Hutton J, Rutter M. Adult outcome for children with autism. J Child Psychol Psychiatry 2004; 45(2): 212-29.[http://dx.doi.org/10.1111/j.1469-7610.2004.00215.x] [PMID: 14982237] ]. As a result, the meaningfulness of prevalence estimate for a mixed ID/non-ID study populations is limited, unless separate data for both groups is also reported. Ideally, patients with ID should be further sub grouped according to severity of ID, as risk of ASD increases with increasing severity of ID [8Brugha TS, Spiers N, Bankart J, et al. Epidemiology of autism in adults across age groups and ability levels. Br J Psychiatry 2016; 209(6): 498-503.[http://dx.doi.org/10.1192/bjp.bp.115.174649] [PMID: 27388569] ].

There was limited evidence among eligible studies pertaining to inpatient prevalence among non-ID adult patients; however, the only eligible study by Mandell et al. [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] ] yielded a prevalence of 5.6%, much higher than widely accepted community prevalence estimates for this group [7Baxter AJ, Brugha TS, Erskine HE, Scheurer RW, Vos T, Scott JG. The epidemiology and global burden of autism spectrum disorders. Psychol Med 2015; 45(3): 601-13.[http://dx.doi.org/10.1017/S003329171400172X] [PMID: 25108395] ]. Clearly more research in non-ID inpatient populations is required to discern whether this result is valid and generalizable.

Additionally, there were no eligible studies focussed on ASD prevalence among groups of patients with discrete mental disorders, such as schizophrenia. This is an important area for future research, as it would shed light on both the extent of ASD comorbidity with specific conditions, as well as further explore diagnostic overshadowing in this context.

The data on inpatients with ID showed significant variability in terms of prevalence estimates, ranging from 4-19.6%. Given the wide-ranging estimates from studies conducted over a considerable time period, it is impossible to assert with confidence whether this represents a significantly different prevalence than in patients with ID in the community setting [43Cooper SA, Smiley E, Morrison J, Williamson A, Allan L. Mental ill-health in adults with intellectual disabilities: Prevalence and associated factors. Br J Psychiatry 2007; 190: 27-35.[http://dx.doi.org/10.1192/bjp.bp.106.022483] [PMID: 17197653] ].

All eligible studies were focussed on predominantly male study populations. Of the two studies reporting data on gender differences, one described non-statistically significant differences (p> 0.05) in ASD prevalence between males and females [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] ] and the other [23Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.] reported a higher prevalence rate among males of those whom were subjected to diagnostic assessment, though did not comment on whether this was statistically significant. Further work needs to be done to determine whether there is a difference in ASD prevalence in the psychiatric inpatient setting, as well as more generally. There has been a long-held belief that ASD is more prevalent in males than females, particularly in those without ID [44Fombonne E. Epidemiological surveys of autism and other pervasive developmental disorders: An update. J Autism Dev Disord 2003; 33(4): 365-82.[http://dx.doi.org/10.1023/A:1025054610557] [PMID: 12959416] ], though it is being increasingly questioned whether this represents a ‘true difference’, or is attributable to other factors, such as ASD screening and diagnostic tests being insufficiently sensitive for females [45Constantino JN, Charman T. Gender bias, female resilience, and the sex ratio in autism. J Am Acad Child Adolesc Psychiatry 2012; 51(8): 756-8.[http://dx.doi.org/10.1016/j.jaac.2012.05.017] [PMID: 22840545] ], and/or females possibly having a greater ability to mask their symptoms (so-called ‘camouflaging’) [46Lai MC, Lombardo MV, Ruigrok AN, et al. Quantifying and exploring camouflaging in men and women with autism. Autism 2017; 21(6): 690-702.[http://dx.doi.org/10.1177/1362361316671012] [PMID: 27899710] ].

Based on the findings from the eligible studies, including those conducted in a forensic setting [22Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327] , 23Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.], there appears to be a general trend suggestive of an increased prevalence of ASD within inpatient psychiatric settings. This data from forensic units could however be confounded by other factors, such as a lack of data on the number of individuals with ID in both studies. While it is conceivable that the clinical features present in ASD, such as abnormal social interaction and communication, could predispose someone to offending, there is limited evidence to support the notion that people with ASD are at any greater risk of committing crimes than the non-ASD population, with the possible exceptions of arson and sexual abuse [47Mouridsen SE. Current status of research on autism spectrum disorders and offending. Res Autism Spectr Disord 2012; 6(1): 79-86.[http://dx.doi.org/10.1016/j.rasd.2011.09.003] ]. Furthermore, even if there were an increased risk of offending behaviours in those with ASD, this would not necessarily manifest itself as an increased prevalence within a forensic psychiatric inpatient setting, as many individuals with ASD may remain undiagnosed, avoid conviction for their offences or be dealt with via the criminal justice system route.

Several studies employed a multiple-stage study design, involving use of a screening tool to determine those whom progress to more comprehensive diagnostic assessment. Such an approach has similarly been used in community-based ASD prevalence studies in both child [48Baird G, Simonoff E, Pickles A, et al. Prevalence of disorders of the autism spectrum in a population cohort of children in South Thames: the Special Needs and Autism Project (SNAP). Lancet 2006; 368(9531): 210-5.[http://dx.doi.org/10.1016/S0140-6736(06)69041-7] [PMID: 16844490] , 49Kim YS, Leventhal BL, Koh YJ, et al. Prevalence of autism spectrum disorders in a total population sample. Am J Psychiatry 2011; 168(9): 904-12.[http://dx.doi.org/10.1176/appi.ajp.2011.10101532] [PMID: 21558103] ] and adult populations [50Brugha TS, McManus S, Smith J, et al. Validating two survey methods for identifying cases of autism spectrum disorder among adults in the community. Psychol Med 2012; 42(3): 647-56.[http://dx.doi.org/10.1017/S0033291711001292] [PMID: 21798110] ]. This is logistically sensible, as many of the ASD diagnostic assessment tools are informant dependent and resource intensive, requiring a considerable amount of time and specialist input [50Brugha TS, McManus S, Smith J, et al. Validating two survey methods for identifying cases of autism spectrum disorder among adults in the community. Psychol Med 2012; 42(3): 647-56.[http://dx.doi.org/10.1017/S0033291711001292] [PMID: 21798110] ]. For these reasons, a multiple-stage approach enables coverage of a larger patient population per unit of resources [51Elsabbagh M, Divan G, Koh YJ, et al. Global prevalence of autism and other pervasive developmental disorders. Autism Res 2012; 5(3): 160-79.[http://dx.doi.org/10.1002/aur.239] [PMID: 22495912] ]. Of course, the value of such an approach is contingent on the validity and reliability of both the constituent screening and diagnostic tests used.

Diagnostic criteria can have a profound effect on the resultant prevalence estimate; as a community population-based study by Cooper et al. [43Cooper SA, Smiley E, Morrison J, Williamson A, Allan L. Mental ill-health in adults with intellectual disabilities: Prevalence and associated factors. Br J Psychiatry 2007; 190: 27-35.[http://dx.doi.org/10.1192/bjp.bp.106.022483] [PMID: 17197653] ] demonstrated, where ASD prevalence among the same group of 1,023 individuals with ID varied from 2.0-4.4% depending on the diagnostic criteria used, and yielded a value of 7.5% for clinical diagnosis by a specialist, considered the gold standard. Also, the eligible studies were published across a period of 30 years and over that time the diagnostic criteria and overall concept of ASD as a clinical entity have broadened considerably [9Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667] , 20American Psychiatric Association Diagnostic and statistical manual of mental disorders, 4th edn (DSM-IV) Washington: American Psychiatric Association 1994 -22Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327] ]

In conclusion, there is a clear need for robustly conducted epidemiological research pertaining to the prevalence of ASD among adults in psychiatric inpatient settings, as the current evidence base is lacking. Such research needs to carefully consider the assessment tools and diagnostic criteria used, as well as a study design supporting coverage of a large patient group. Additionally, the characteristics of the study population need to be appropriately detailed, with prevalence estimates for ID and non-ID groups and both genders as a bare minimum requirement. Adult psychiatric inpatient populations could indeed potentially provide a target for identifying those with ASD, though it is first essential to first establish whether ASD is truly significantly more prevalent in people within this group relative to the community setting.

NOTES

Not referred to as the ASDASQ within the article itself, as the tool was (at the time of the Hare et al article being published) an unnamed, unpublished screening tool (which was later named the ASDASQ).

Confirmed via correspondence with Dr David Mandell.

Referred to as a ‘mental handicap hospital’ within the source article.

ETHICS APPROVAL AND CONSENT TO PARTICIPATE

Not applicable.

CONSENT FOR PUBLICATION

Not applicable.

CONFLICT OF INTEREST

The authors confirm that this article content has no conflict of interest.

ACKNOWLEDGEMENTS

The authors would like to thank Freya Tyrer and Mary Edmunds Otter at the East Midlands NIHR Research Design Service Tanya McLaven and Stuart Glover at University Hospitals of Leicester for their support with the literature search process. They also wish to thank Dr David Mandell and Dr Tanja Sappok for kindly responding to questions pertaining to their articles.

SUPPLEMENTARY MATERIAL

Supplementary material is available on the publishers Website along with the published article.

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REFERENCES

[1] The ICD-10 classification of mental and behavioural disorders: clinical descriptions and diagnostic guidelines 1992.
[2] Witwer AN, Lecavalier L. Examining the validity of autism spectrum disorder subtypes. J Autism Dev Disord 2008; 38(9): 1611-24.[http://dx.doi.org/10.1007/s10803-008-0541-2] [PMID: 18327636]
[3] Howlin P, Goode S, Hutton J, Rutter M. Adult outcome for children with autism. J Child Psychol Psychiatry 2004; 45(2): 212-29.[http://dx.doi.org/10.1111/j.1469-7610.2004.00215.x] [PMID: 14982237]
[4] Lai MC, Baron-Cohen S. Identifying the lost generation of adults with autism spectrum conditions. Lancet Psychiatry 2015; 2(11): 1013-27.[http://dx.doi.org/10.1016/S2215-0366(15)00277-1] [PMID: 26544750]
[5] Murphy CM, Wilson CE, Robertson DM, et al. Autism spectrum disorder in adults: diagnosis, management, and health services development. Neuropsychiatr Dis Treat 2016; 12: 1669-86.[http://dx.doi.org/10.2147/NDT.S65455] [PMID: 27462160]
[6] Garland J, O’Rourke L, Robertson D. Autism spectrum disorder in adults: Clinical features and the role of the psychiatrist. Adv Psychiatr Treat 2013; 19(5): 378-91.[http://dx.doi.org/10.1192/apt.bp.112.010439]
[7] Baxter AJ, Brugha TS, Erskine HE, Scheurer RW, Vos T, Scott JG. The epidemiology and global burden of autism spectrum disorders. Psychol Med 2015; 45(3): 601-13.[http://dx.doi.org/10.1017/S003329171400172X] [PMID: 25108395]
[8] Brugha TS, Spiers N, Bankart J, et al. Epidemiology of autism in adults across age groups and ability levels. Br J Psychiatry 2016; 209(6): 498-503.[http://dx.doi.org/10.1192/bjp.bp.115.174649] [PMID: 27388569]
[9] Mandell DS, Lawer LJ, Branch K, et al. Prevalence and correlates of autism in a state psychiatric hospital. Autism 2012; 16(6): 557-67.[http://dx.doi.org/10.1177/1362361311412058] [PMID: 21846667]
[10] Gillberg C, Billstedt E. Autism and Asperger syndrome: coexistence with other clinical disorders. Acta Psychiatr Scand 2000; 102(5): 321-30.[http://dx.doi.org/10.1034/j.1600-0447.2000.102005321.x] [PMID: 11098802]
[11] Hofvander B, Delorme R, Chaste P, et al. Psychiatric and psychosocial problems in adults with normal-intelligence autism spectrum disorders. BMC Psychiatry 2009; 9(1): 35.[http://dx.doi.org/10.1186/1471-244X-9-35] [PMID: 19515234]
[12] Ghaziuddin M, Ghaziuddin N, Greden J. Depression in persons with autism: implications for research and clinical care. J Autism Dev Disord 2002; 32(4): 299-306.[http://dx.doi.org/10.1023/A:1016330802348] [PMID: 12199134]
[13] Croen LA, Zerbo O, Qian Y, et al. The health status of adults on the autism spectrum. Autism 2015; 19(7): 814-23.[http://dx.doi.org/10.1177/1362361315577517] [PMID: 25911091]
[14] Mazzone L, Ruta L, Reale L. Psychiatric comorbidities in asperger syndrome and high functioning autism: diagnostic challenges. Ann Gen Psychiatry 2012; 11(1): 16.[http://dx.doi.org/10.1186/1744-859X-11-16] [PMID: 22731684]
[15] Larson FV, Wagner AP, Jones PB, et al. Psychosis in autism: Comparison of the features of both conditions in a dually affected cohort. Br J Psychiatry 2017; 210(4): 269-75.[http://dx.doi.org/10.1192/bjp.bp.116.187682] [PMID: 27979819]
[16] Strømme P, Diseth TH. Prevalence of psychiatric diagnoses in children with mental retardation: Data from a population-based study. Dev Med Child Neurol 2000; 42(4): 266-70.[http://dx.doi.org/10.1017/S0012162200000451] [PMID: 10795566]
[17] Emerson E, Baines S. The estimated prevalence of autism among adults with learning disabilities in England 2010.
[18] American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 5th edn (DSM-5). Arlington: American Psychiatric Publishing 2013.
[19] American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 3rd edn (DSM-III). Washington: American Psychiatric Association 1980.
[20] American Psychiatric Association Diagnostic and statistical manual of mental disorders, 4th edn (DSM-IV) Washington: American Psychiatric Association 1994
[21] Vandenbroucke JP, von Elm E, Altman DG, et al. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): explanation and elaboration. PLoS Med 2007; 4(10): e297.[http://dx.doi.org/10.1371/journal.pmed.0040297] [PMID: 17941715]
[22] Scragg P, Shah A. Prevalence of Asperger’s syndrome in a secure hospital. Br J Psychiatry 1994; 165(5): 679-82.[http://dx.doi.org/10.1192/bjp.165.5.679] [PMID: 7794327]
[23] Hare DJ, Gould J, Mills R, Wing L. A preliminary study of individuals with autistic spectrum disorders in three special hospitals in England 1999.
[24] Shah A, Holmes N, Wing L. Prevalence of autism and related conditions in adults in a mental handicap hospital. Appl Res Ment Retard 1982; 3(3): 303-17.[http://dx.doi.org/10.1016/0270-3092(82)90022-4] [PMID: 7149707]
[25] Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 2009; 6(7): e1000097.[http://dx.doi.org/10.1371/journal.pmed.1000097] [PMID: 19621072]
[26] Nylander L, Gillberg C. Screening for autism spectrum disorders in adult psychiatric out-patients: A preliminary report. Acta Psychiatr Scand 2001; 103(6): 428-34.[http://dx.doi.org/10.1034/j.1600-0447.2001.00175.x] [PMID: 11401656]
[27] Wing L. The MRC handicaps, behaviour & skills (HBS) schedule. Acta Psychiatr Scand 1980; 62(S285): 241-8.[http://dx.doi.org/10.1111/j.1600-0447.1980.tb07696.x]
[28] Constantino JN, Gruber CP. Social Responsiveness Scale (SRS) 2012.
[29] Nurnberger JI Jr, Blehar MC, Kaufmann CA, et al. Diagnostic interview for genetic studies. Rationale, unique features, and training. Arch Gen Psychiatry 1994; 51(11): 849-59.[http://dx.doi.org/10.1001/archpsyc.1994.03950110009002] [PMID: 7944874]
[30] Lord C, Rutter M, Le Couteur A. Autism Diagnostic Interview-Revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. J Autism Dev Disord 1994; 24(5): 659-85.[http://dx.doi.org/10.1007/BF02172145] [PMID: 7814313]
[31] Gillberg IC, Gillberg C. Asperger syndrome-some epidemiological considerations: a research note. J Child Psychol Psychiatry 1989; 30(4): 631-8.[http://dx.doi.org/10.1111/j.1469-7610.1989.tb00275.x] [PMID: 2670981]
[32] Holmes N, Shah A, Wing L. The Disability Assessment Schedule: A brief screening device for use with the mentally retarded. Psychol Med 1982; 12(4): 879-90.[http://dx.doi.org/10.1017/S0033291700049175] [PMID: 7156257]
[33] Ferriter M, Hare D, Bendall P, et al. Brief report: Assessment of a screening tool for autistic spectrum disorders in adult population. J Autism Dev Disord 2001; 31(3): 351-3.[http://dx.doi.org/10.1023/A:1010755505774] [PMID: 11518488]
[34] Turygin N, Matson JL, Adams H. Prevalence of co-occurring disorders in a sample of adults with mild and moderate intellectual disabilities who reside in a residential treatment setting. Res Dev Disabil 2014; 35(7): 1802-8.[http://dx.doi.org/10.1016/j.ridd.2014.01.027] [PMID: 24656808]
[35] Esan F, Chester V, Gunaratna IJ, Hoare S, Alexander RT. The clinical, forensic and treatment outcome factors of patients with autism spectrum disorder treated in a forensic intellectual disability service. J Appl Res Intellect Disabil 2015; 28(3): 193-200.[http://dx.doi.org/10.1111/jar.12121] [PMID: 25379816]
[36] Gustafsson C. The prevalence of people with intellectual disability admitted to general hospital psychiatric units: level of handicap, psychiatric diagnoses and care utilization. J Intellect Disabil Res 1997; 41(Pt 6): 519-26.[http://dx.doi.org/10.1111/j.1365-2788.1997.tb00745.x] [PMID: 9430057]
[37] Lyall R, Kelly M. Specialist psychiatric beds for people with learning disability. Psychiatr Bull 2007; 31(8): 297-300.[http://dx.doi.org/10.1192/pb.bp.106.011700]
[38] Heinrich M, Böhm J, Sappok T. Diagnosing Autism in Adults with Intellectual Disability: Validation of the DiBAS-R in an Independent Sample. J Autism Dev Disord 2018; 48(2): 341-50.[http://dx.doi.org/10.1007/s10803-017-3336-5] [PMID: 28988347]
[39] Sappok T, Heinrich M, Diefenbacher A. Psychometrische Eigenschaften der Autismus-Checkliste (ACL) für erwachsene Menschen mit Intelligenzminderung. Psychiatr Prax 2014; 41(1): 37-44.[PMID: 23681789]
[40] Lord C, Risi S, Lambrecht L, et al. The autism diagnostic observation schedule-generic: A standard measure of social and communication deficits associated with the spectrum of autism. J Autism Dev Disord 2000; 30(3): 205-23.[http://dx.doi.org/10.1023/A:1005592401947] [PMID: 11055457]
[41] Kraijer D, de Bildt A. The PDD-MRS: An instrument for identification of autism spectrum disorders in persons with mental retardation. J Autism Dev Disord 2005; 35(4): 499-513.[http://dx.doi.org/10.1007/s10803-005-5040-0] [PMID: 16134035]
[42] Bergmann T, Sappok T, Diefenbacher A, et al. Music-based Autism Diagnostics (MUSAD) - A newly developed diagnostic measure for adults with intellectual developmental disabilities suspected of autism. Res Dev Disabil 2015; 43-44: 123-35.[http://dx.doi.org/10.1016/j.ridd.2015.05.011] [PMID: 26183337]
[43] Cooper SA, Smiley E, Morrison J, Williamson A, Allan L. Mental ill-health in adults with intellectual disabilities: Prevalence and associated factors. Br J Psychiatry 2007; 190: 27-35.[http://dx.doi.org/10.1192/bjp.bp.106.022483] [PMID: 17197653]
[44] Fombonne E. Epidemiological surveys of autism and other pervasive developmental disorders: An update. J Autism Dev Disord 2003; 33(4): 365-82.[http://dx.doi.org/10.1023/A:1025054610557] [PMID: 12959416]
[45] Constantino JN, Charman T. Gender bias, female resilience, and the sex ratio in autism. J Am Acad Child Adolesc Psychiatry 2012; 51(8): 756-8.[http://dx.doi.org/10.1016/j.jaac.2012.05.017] [PMID: 22840545]
[46] Lai MC, Lombardo MV, Ruigrok AN, et al. Quantifying and exploring camouflaging in men and women with autism. Autism 2017; 21(6): 690-702.[http://dx.doi.org/10.1177/1362361316671012] [PMID: 27899710]
[47] Mouridsen SE. Current status of research on autism spectrum disorders and offending. Res Autism Spectr Disord 2012; 6(1): 79-86.[http://dx.doi.org/10.1016/j.rasd.2011.09.003]
[48] Baird G, Simonoff E, Pickles A, et al. Prevalence of disorders of the autism spectrum in a population cohort of children in South Thames: the Special Needs and Autism Project (SNAP). Lancet 2006; 368(9531): 210-5.[http://dx.doi.org/10.1016/S0140-6736(06)69041-7] [PMID: 16844490]
[49] Kim YS, Leventhal BL, Koh YJ, et al. Prevalence of autism spectrum disorders in a total population sample. Am J Psychiatry 2011; 168(9): 904-12.[http://dx.doi.org/10.1176/appi.ajp.2011.10101532] [PMID: 21558103]
[50] Brugha TS, McManus S, Smith J, et al. Validating two survey methods for identifying cases of autism spectrum disorder among adults in the community. Psychol Med 2012; 42(3): 647-56.[http://dx.doi.org/10.1017/S0033291711001292] [PMID: 21798110]
[51] Elsabbagh M, Divan G, Koh YJ, et al. Global prevalence of autism and other pervasive developmental disorders. Autism Res 2012; 5(3): 160-79.[http://dx.doi.org/10.1002/aur.239] [PMID: 22495912]

Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


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