Is treatment for bipolar disorder more effective earlier in illness course? A comprehensive literature review

BACKGROUND We aimed to investigate a key element of the early intervention approach whether treatment at an earlier stage of bipolar disorder is more effective than later in its course. METHODS A comprehensive literature review using Medline, Embase, Psychinfo, PsycArticle, and Web of Science, as data sources, with a subsequent narrative synthesis. Study quality was assessed using the Cochrane risk of bias method. RESULTS Our search strategy yielded eight primary papers and two meta-analyses (of psychological therapies and Olanzapine) in total representing 8942 patients. Five studies focused on comparisons between first and multiple episodes, and the others on fewer vs more episode categories. There was a consistent finding, suggesting treatment in earlier illness stage resulted in better outcomes in terms of response, relapse rate, time to recurrence, symptomatic recovery, remission, psychosocial functioning, and employment. This effect was found for pharmacological (Lithium, Olanzapine, Divalproex) and psychological treatments. LIMITATIONS There was high risk of selection, performance, and attrition bias in most studies. First admission or presentation is unlikely to equate to first episode, because of the duration of untreated illness. Some patients having experienced multiple episodes could be "treatment resistant". Study heterogeneity precluded meta-analysis. CONCLUSIONS Psychological and pharmacological treatments in the early stages of illness are more effective than in the later stages of bipolar disorder across multiple domains. There is a first episode and the early phase effect. Consistent with the staging model of illness, findings provide evidence for the clinical utility of an early intervention approach in bipolar disorder to improve patient outcomes.