Table 5: Confounding Factors which are Known to Exert an Independent Effect on Cognition. Factors Ultimately Identified in the Analyses are Highlighted in Bold

Stroop Word Interference	Free Recall Words Recalled	Simple Reaction Time Mean Reaction Time	Repeated Digits Task Digits Detected
Gender Age Educational Status Employment Status NART	Age Marital Status Educational Status Employment Status Social Classification NART	Gender Marital Status Educational Status Employment Status Social Classification NART	Gender Educational Status Employment Status Social Classification NART
Rested by sleep	Rested by sleep	Medication Rested by sleep	Rested by sleep
Emotional Distress Cognitive Difficulties Somatic Symptoms Physical Symptoms	Emotional Distress Cognitive Difficulties Somatic Symptoms Physical Symptoms	Emotional Distress Cognitive Difficulties Somatic Symptoms Physical Symptoms	Emotional Distress Cognitive Difficulties Somatic Symptoms
Depression Trait Anxiety Positive Mood Negative Mood Cognitive Failures	Depression Trait Anxiety Positive Mood Negative Mood Cognitive Failures	Depression Trait Anxiety Positive Mood Negative Mood Cognitive Failures	Depression Positive Mood Cognitive Failures
Daily Hassles Perceived Stress	Daily Hassles Perceived Stress	Daily Hassles Perceived Stress	Daily Hassles