Contribution of depressive symptom load on prediction of transition to bipolar disorders: Results from the prospective-longitudinal multi-method Early-BipoLife study

BACKGROUND: Depressive episodes are associated with a higher risk for the onset of bipolar disorder (BD). This study investigates the contribution of specific depressive symptoms using a multi-method approach in persons at-risk for bipolar disorders. METHODS: In the Early-BipoLife study, N = 1083 participants at risk for BD were examined over two years (baseline, 6, 12, 18, and 24 months). Out of 1083 participants, N = 57 (5.3%) transitioned to BD and/or were prescribed with a mood stabilizing medication (lithium, lamotrigine, valproic acid, carbamazepine, quetiapine). At baseline, N = 880 participants met the diagnostic criteria for lifetime major depression (lifetime MD) (SCID). Depressive symptoms were recorded using diagnostic interviews (EPIbipolar, SCID), a clinician rating (ICD-C) and a self-rating (QIDS-SR16). Binary logistic regressions were calculated to assess the prospective association between depressive symptoms and transition/prescription of a mood stabilizing medication. RESULTS: Compared to 'no lifetime MD', 'lifetime MD' were at higher risk for transition and/or prescription of a mood stabilizing medication (OR = 2.87, 95%CI: 1.03-8.04). A higher QIDS-SR16 symptom load was associated with transition and/or prescription of a mood stabilizing medication (OR = 1.07, 95%CI: 1.01-1.13). Consistently and across methods, it was shown that suicidality at baseline predicted transition to BD and/or prescription of a mood stabilizing medication. Further baseline symptoms assessed by the clinicians (IDS-C), such as decreased or increased appetite and quality of mood were also predictive for this outcome. CONCLUSION: Depressive symptom load and suicidality were robust predictors for BD. Clinician judgment can provide important information for early detection of BD.