Background: It has been proposed that antidepressants can induce a chronic, dysphoric, irritable state in bipolar patients (called ACID for antidepressant-associated chronic irritable dysphoria). This phenomenon has only been described in case series format, and has not been prospectively validated.
Methods: Prospective data from the first 1500 patients (62.7% with bipolar I, 30.1% with bipolar II, and 7.2% with NOS) treated in the STEP-BD database were examined and those who were euthymic for at least one month at study entry, subsequently developed a depressive episode, and were then followed for one year were identified. Outcome of those who received an antidepressant for this depressive episode (n=27) was compared to those who did not (n=56), with particular attention given to the presence of the proposed symptom triad of ACID, namely dysphoria, irritability, and middle insomnia.
Results: Patients treated with antidepressants were ten times more likely to develop ACID than those who were not (Hazard ratio=9.95, CI=1.103-89.717, P=0.04). However, the hazard ratio dropped to 1.05 (P=0.99) when corrected for significant covariates, notably past antidepressant-related manic switch and sex.
Discussion: This study does not support the existence of ACID as an independent phenomenon. Rather, ACID appears to be part of a broader spectrum of antidepressant treatment-emergent affective switches.