Clinical and demographic features of mood disorder subtypes

The aim of this study was to investigate demographic, clinical and symptomatologic features of the following mood disorder subtypes: bipolar disorder I (BP-I); bipolar disorder II (BP-II); major depressive disorder, recurrent (MDR); and major depressive episode, single episode (MDSE). A total of 1832 patients with mood disorders (BP-I=863, BP-II=141, MDR=708, and MDSE=120) were included in our study. The patients were assessed using structured diagnostic interviews and the operational criteria for psychotic illness checklist (n=885), the Hamilton depression rating scale (n=167), and the social adjustment scale (n=305). The BP-I patients were younger; had more hospital admissions; presented a more severe form of symptomatology in terms of psychotic symptoms, disorganization, and atypical features; and showed less insight into their disorder than patients in the other groups. Compared with the major depressive subgroups, BP-I patients were more likely to have an earlier age at onset, an earlier first lifetime psychiatric treatment, and a greater number of illness episodes. BP-II patients had a higher suicide risk than both BP-I and MDSE patients. MDSE patients presented less severe symptomatology, lower age at observation, and a higher number of males. The retrospective approach and the selection constraints due to the inclusion criteria are the main limitations of the study. Our data support the view that BP-I disorder is quite different from the remaining mood disorders from a demographic and clinical perspective, with BP-II disorder having an intermediate position to MDR and MDSE, that is, as a less severe disorder. This finding may help in the search for the biological basis of mood disorders.