Residual symptoms predict recurrence in bipolar disorder

The results of a recent study indicate that mood episodes in bipolar disorder are prevalent and are likely to recur in spite of guideline-based treatments, highlighting the need for new interventions.US researchers analysed prospective follow-up data for 1,469 patients with bipolar disorder who were participating in a larger study - the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD).The aim of the analysis was to investigate recurrence among patients who initially achieved recovery from a mood episode to estimate the effectiveness of guideline-based treatment with contemporary pharmacotherapies, and to determine predictors of recurrence.All patients were in a symptomatic state on enrolment into the STEP-BD, of which 858 (58.4%) achieved recovery (defined as two or fewer syndromal features of mania, hypomania, or depression for at least eight weeks) during two years of follow-up.Cox regression models were used to examine the association between individual predictors and time to recurrence (defined as meeting full DSM-IV criteria for a manic, hypomanic, mixed or depressive episode at any follow-up visit) in patients who achieved recovery during follow-up.Recurrence was observed in 416 patients (48.5%) during follow-up, with depressive episodes developing in almost twice as many patients as mood elevation episodes (34.7% versus 13.8%). Time taken until 25% of the participants experienced a depressive episode was 21.4 weeks compared with 85.0 weeks for a manic/hypomanic/mixed episode.A current substance abuse disorder at study entry was associated with an increased risk of manic but not depressive recurrence, while current anxiety diagnosis at study entry was associated with an increased risk of depressive but not manic recurrence.Patients with more than 20 previous episodes of depression or mania/hypomania were more likely to experience recurrence to that pole. Residual depressive or manic symptoms were also associated with a greater risk of depression, with risk of depressive recurrence shown to increase by 14% for every depressive symptom and by 20% for every manic/hypomanic symptom present at recovery.The proportion of time spent in a manic/hypomanic state in the past year was associated with shorter time to manic/hypomanic/mixed episode recurrence, while a greater proportion of time spent depressed or anxious was associated with depressive recurrence.The fact that early residual symptoms predict risk of recurrence highlights the need to target full remission, as in major depressive disorder, the researchers conclude.They add: "A better understanding of the way in which these predictors may moderate (or mediate) risk of recurrence could also suggest directions towards novel strategies to modify this risk".Reference...