Mazzarini L, et al. - Here, the physicians determined bipolar/mixed feature frequency in a large major depressive disorder (MDD) multinational sample with (High-Rec) and without (Low-Rec) >3 recurrences, comparing the 2 subsamples. For several clinical/epidemiological variables, including bipolar/mixed features, High-Rec MDD differed from Low-Rec group. Compared to DSM-5 criteria, bipolarity specifier and research-based diagnostic criteria (RBDC) were more sensitive in detecting bipolar and mixed features in MDD.