Brief major depressive episode as an essential predictor of the Bipolar Spectrum Disorder

BACKGROUND: A bipolar spectrum definition presented to help the designation of more appropriate diagnostic criteria for the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-V) is Ghaemi et al. Bipolar Spectrum Disorder (BSD). The present study evaluates the BSD frequency among inpatients with major depressive disorder (MDD) and tries to elucidate the contribution of second degree diagnostic items of BSD in the BSD definition. METHODS: One hundred individuals aged 18-65 with current MDD consecutive admitted in three university affiliated psychiatric center were clinically interviewed. The patients with mental retardation or the history of substance dependence/ abuse were excluded. The interviews were carried out by a trained general practitioner according to an 11-item checklist comprised of criteria C (2 items) and D (9 items) of Ghaemi et al. BSD. RESULTS: Fifty three males and 47 females entered the study. Patients’ mean age was 34.16 ± 9.58. Thirty eight patients (39.2%: 18 males and 20 females) met the complete diagnostic criteria of BSD. Early onset depression (53.0%), recurrent depression (40.0%) and treatment resistant depression (38.8%) were the most frequent accessory items of BSD, but using logistic regression three items recurrent major depressive episodes (MDEs), treatment resistant depression, and brief MDE- had the significant weight to predict the BSD. Then, three mentioned items were simultaneously entered the logistic regression model: brief MDE (β = 1.5, EXP (β) = 4.52, p = 0.007), treatment resistant depression (β = 1.28, EXP (β) = 3.62, p = 0.01), and recurrent MDEs (β = 1.28, EXP (β) = 3.62, p = 0.01) had the highest strength in predicting BSD and account for 21-30% of BSD diagnosis variance in sum. CONCLUSIONS: Regarding the greater diagnostic strength of some accessory items – especially brief MDE – to predict the BSD, it is suggested that these items were considered as the main ones in the BSD criterion C.