Early Improvement of Specific Symptoms Predicts Subsequent Recovery in Bipolar Depression: Reanalysis of the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) Data.

OBJECTIVE

The aim of this post hoc analysis was to evaluate which specific depressive items could predict subsequent durable recovery in patients with bipolar depression.

METHODS

The study population was at least 18 years old and met DSM-IV criteria for a major depressive episode associated with either bipolar I or II disorder. The data were derived from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD), in which patients with bipolar depression were randomly assigned to treatment for acute depression with a mood stabilizer plus an adjunctive antidepressant drug or placebo. The primary and secondary outcomes were durable recovery (ie, 8 consecutive weeks of euthymia) and treatment-emergent affective switch (ie, transition to mania or hypomania), respectively. Binary logistic regression analysis was performed to identify specific symptoms whose improvement during the first 2 weeks predicted those outcomes; the score change of each individual symptom in the continuous symptom subscales for depression (SUM-D) from week 0 to week 2 was used as an independent variable.

RESULTS

In the evaluable 188 participants who took placebo and active drugs, the improvement in loss of self-esteem (P = .037) or loss of energy (P = .040) at week 2 was significantly associated with higher chances of subsequent durable recovery. For participants taking active drugs (n = 91), solely the improvement in loss of energy at week 2 was significantly associated with subsequent durable recovery (P = .027). There was a significant association between the improvement of psychomotor retardation at week 2 and subsequent affective switch (P = .008).

CONCLUSIONS

These findings imply that focusing on individual symptoms is important in bipolar depression, rather than relying solely on a summed score in rating scales.

TRIAL REGISTRATION: The original STEP-BD dataset is registered on ClinicalTrials.gov (identifier: NCT00012558).