Background: Identifying the bipolar (BP) spectrum, including the classic Bipolar I subtype (BP-I), Bipolar II (BP-II) and subthreshold bipolar disorders not meeting DSM-IV diagnostic criteria has raised growing interest, as these softer expressions of bipolar spectrum have been underdiagnosed in spite of clinical consequences.
Methods: Data are from the Sao Paulo Epidemiological Catchment Area Study (N=1464). Non-affective controls were compared to BP spectrum groups, based on DSM-IIIR and on the "clinical significance" criteria: Subsyndromal Hypomania (SSH) and Manic Symptoms (MS).
Results: The lifetime prevalence of BP subgroups was 8.3% (N=122). All BP-I and -II and around 75% of SSH and MS subjects had a lifetime depressive syndrome. Compared to controls and MS subjects, BP-I, BP-II and SSH groups searched more medical help and mental health services. SSH group displayed higher rates of clinical significance than BP-I subjects, and suicidality was higher in BP groups compared to controls. Even the softer MS group had higher rate of suicide attempts than SSH subjects.
Limitations: This is a cross-sectional study and interviews were conducted by lay personnel. Replication in bigger community samples using a mood spectrum approach is necessary to confirm these findings. However, our findings were very similar to those obtained by other authors.
Conclusion: Softer expressions of BP disorders appear in 6.6% of this community sample and have serious clinical consequences, which supports the importance of including these categories in the BP spectrum.