Relationship of a big five personality questionnaire to the symptoms of affective disorders.

Online assessments allow cost-effective, large-scale screening for psychiatric vulnerability (e.g., university undergraduates or military recruits). However, conventional psychiatric questionnaires may worsen mental health outcomes due to overmedicalizing normal emotional reactions. Personality questionnaires designed for occupational applications could circumvent this problem as they utilise non-clinical wording and it is well-established that personality traits influence susceptibility to psychiatric illness. Here we present a brief, free-to-use occupational personality questionnaire, and test its sensitivity to symptoms of Bipolar Disorder (BD) and Major Depressive Disorder (MDD) in an online sample. Our study used a cross-sectional, self-report design to assess the relationship between self-reported symptoms of affective disorders and scores on the personality dimensions of openness, conscientiousness, extraversion, agreeableness and neuroticism. We used SEM to compare affective symptoms in 8,470 individuals (mean age 25.6 ± 7.0 years; 4,717 male) with scores on an online adaption of the TSDI, a public-domain 'Big Five' personality questionnaire. ROC curve analyses assessed cut off scores for the best predictors of overall vulnerability to affective disorders (represented by a composite screening score). Neuroticism was the most robust predictor of QIDS-16 depression symptoms and MDQ Hypomania symptoms (β = 0.68 and 0.39 respectively, p < .0001). Extraversion was the most robust predictor of HCL-16 Hypomania symptoms (β = 0.34, p < .0001). ROC curve analyses suggest if the TSDI was used for screening in this sample, neuroticism cut offs of approximately 58 for men and 70 for women would provide the most useful classification of overall vulnerability to affective disorders.