Affective instability and the course of bipolar depression: results from the STEP-BD randomised controlled trial of psychosocial treatment

BACKGROUND: Little is known about predictors of recovery from bipolar depression. AIMS: We investigated affective instability (a pattern of frequent and large mood shifts over time) as a predictor of recovery from episodes of bipolar depression and as a moderator of response to psychosocial treatment for acute depression. METHOD: A total of 252 out-patients with DSM-IV bipolar I or II disorder and who were depressed enrolled in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) and were randomised to one of three types of intensive psychotherapy for depression (n = 141) or a brief psychoeducational intervention (n = 111). All analyses were by intention-to-treat. RESULTS: Degree of instability of symptoms of depression and mania predicted a lower likelihood of recovery and longer time until recovery, independent of the concurrent effects of symptom severity. Affective instability did not moderate the effects of psychosocial treatment on recovery from depression. CONCLUSIONS: Affective instability may be a clinically relevant characteristic that influences the course of bipolar depression.