Commentary

Perlis et al followed 858 outpatients with a diagnosis of bipolar disorder for an average of about one year after recovery. Based on their findings, bipolar disorder, even when treated appropriately, remains a highly recurrent syndrome. Roughly half of the participants experienced a recurrence of a depressive or mood elevated episode over follow up, with depressive recurrences approximately twice as common as mood elevated ones.

Several predictors of recurrence were identified. For example, having spent a greater amount of time in a depressed or anxious state in the recent past predicted a greater likelihood of depressive symptom recurrence in the future, whereas having spent more time in a manic state predicted future mood elevation. Interestingly, a greater number of depressive episodes in the previous year also predicted manic episode recurrence, lending some support to the idea that manic episodes can emerge in response to prior depression. Such findings could be used to support the manic defense hypothesis, which has recently received renewed attention.¹

Several strengths of this study can be highlighted, such as the large sample, prospective design, and careful diagnostic and symptom assessment procedures. The study is important because it demonstrates once again that the risk for recurrence in bipolar disorder remains high, even when it is treated appropriately. An obvious clinical implication is that residual symptoms should be targeted aggressively after initial recovery, which might reduce risk for subsequent symptom intensification. The study identified several demographic and illness related predictors of symptom course, although it did not focus specifically on psychosocial predictors of symptom course, such as expressed emotion, social support, life events, personality, sleep deprivation, or cognitive emotional responses to incentives. Such psychosocial processes, however, may also predict the course of bipolar symptoms² and thus equally deserve attention in future research.