Predominant recurrence polarity among 928 adult international bipolar I disorder patients.

OBJECTIVE: To test the hypothesis that patients with bipolar disorder (BPD) differ demographically and clinically within subgroups based on the predominant-polarity of major recurrences. METHOD: We tested factors for association with predominantly (≥2 : 1) depressive vs. mania-like episodes with 928 DSM-IV type-I BPD subjects from five international sites. RESULTS: Factors preliminarily associated with predominant-depression included: electroconvulsive treatment, longer latency-to-BPD diagnosis, first episode depressive or mixed, more suicide attempts, more Axis-II comorbidity, ever having mixed-states, ever married, and female sex. Predominant-mania was associated with: initial manic or psychotic episodes, more drug abuse, more education, and more family psychiatric history. Of the 47.3% of subjects without polarity-predominance, risks for all factors considered were intermediate. Expanding the definition of polarity-predominance to ≥51% added little, but shifting mixed-states to 'predominant-depression' increased risk of suicidal acts from 2.4- to 4.5-fold excess over predominant-mania-hypomania, and suicidal risk was associated continuously with increasing proportions of depressive or mixed episodes. CONCLUSION: Subtyping by predominant-polarity yielded predictive associations, including the polarity of first episodes and risk of suicide attempts. Such subtyping may contribute to improve planning of clinical care and to biological studies of BPD.

Comparison of antidepressant responses in patients with bipolar vs. unipolar depression: a meta-analytic review.

BACKGROUND: Since there is considerable uncertainty about therapeutic responses to antidepressants among depressed patients diagnosed with bipolar (BP) vs. unipolar (UP) mood disorders, we have reviewed available studies that compared both types of depressed patients. METHODS: Extensive computerized literature-searching identified reports of antidepressant studies involving both BP and UP depressed patients. We used random-effects meta-analysis to compare short-term drug responses by patient type, as well as meta-regression modeling for effects of selected covariates. RESULTS: We identified only 10 studies meeting even liberal inclusion criteria, and they varied greatly in size and design quality. The overall difference in antidepressant responses between BP (n=863) and UP (n=2 226) disorder patients was not significant (pooled RR=1.05; CI: 0.96-1.15; P=0.34). Based on meta-regression, we also found no difference in responses based on diagnosis or subtype, subjects/study, % women, average age, or length of treatment based on meta-regression. Risk of manic-switching averaged 2.50 vs. 0.275%/week among BP vs. UP disorder patients, including co-treatment with mood stabilizers in 70% of BP patients. COMMENTS: The findings suggest little difference in antidepressant responses by diagnostic type, sex, or other factors considered, but a substantial risk of mania and hypomania with BP disorders. However, data pertaining to the fundamental question of antidepressant response among BP vs. UP depressed patients were strikingly limited, and support only tentative conclusions. Additional, well-designed, prospective trials of matched BP and UP depression patients and controlled treatment are required.