Depression across mood disorders: review and analysis in a clinical sample

In this article we aimed to: (1) review literature concerning the clinical and psychopathologic characteristics of Bipolar (BP) depression; (2) analyze an independent sample of depressed patients to identify any demographic and/or clinical feature that may help in differentiating mood disorder subtypes, with special attention to potential markers of bipolarity.

A sample of 291 depressed subjects, including BP -I (n = 104), BP -II (n = 64), and unipolar (UP) subjects with (n = 53) and without (n = 70) BP family history (BPFH), was examined to evidence potential differences in clinical presentation and to validate literature-derived markers of bipolarity. Demographic and clinical variables and, also, single items from the Hamilton Depression Rating Scale (HDRS), the Montgomery-Asberg Depression Rating Scale (MADRS), and the Young Mania Rating Scale (YMRS) were compared among groups.

UP subjects had an older age at onset of mood symptoms. A higher number of major depressive episodes and a higher incidence of lifetime psychotic features were found in BP subjects. Items expressing depressed mood, depressive anhedonia, pessimistic thoughts, and neurovegetative symptoms of depression scored higher in UP, whereas depersonalization and paranoid symptoms' scores were higher in BP. When compared with UP, BP I had a significantly higher incidence of intradepressive hypomanic symptoms. Bipolar family history was found to be the strongest predictor of bipolarity in depression.

Overall, our findings confirm most of the classical signs of bipolarity in depression and support the view that some features, such as BPFH, together with some specific symptoms may help in detecting depressed subjects at higher risk for BP disorder.