Our randomized study investigated neurocognitive performance, such as working memory, verbal and figural
memory, executive functions and psychomotor speed of opioid-dependent patients within a permanent maintenance treatment
programme. Our results indicate that buprenorphine preserve cognitive functions better than methadone, at least when benzodiazepine
comedication is used. Buprenorphine-treated patients showed significantly better results compared to methadone
patients in the verbal memory performance, and this even for the verbal list learning (p = 0.007) as for the delayed recall of
the words (p = 0.012). Furthermore the buprenorphine maintained persons showed statistically significant the more favourable
scores in the working memory performance for figural material (digit symbol test, HAWIE-R) (p = 0.021). Our results
indicate a better cognitive performance also after a longer substitution time and results cannot easily be attributed to an "only"
transient opioid switching effect. Continued research is still needed to confirm the less impairment on cognitive functions.