BACKGROUND: The nosological and clinical implications of psychotic features in the course of mood disorders have been widely debated. Currently, no specification exists for defining a subgroup of lifetime Psychotic Mood Disorder (PMD) patients.
METHODS: A total of 2178 patients were examined, including subjects with Bipolar Disorder (BP) type I (n=519) and II (n=207) and Major Depressive Disorder (n=1452). Patients were divided between PMD (n=645) and non-psychotic Mood Disorders (MD) (n=1533) by the lifetime presence of at least one mood episode with psychotic features. Subjects having a depressive episode at the time of assessment were also examined: HAM-D and YMRS scores were compared between MD and PMD subjects, both with and without current psychotic features.
RESULTS: A diagnosis of BP-I, a higher familial load for BP, a higher number of mood episodes lifetime, and a higher prevalence of OCD and somatic comorbidities were all associated to PMD. A diagnosis of BP (OR=4.48) was the only significant predictor for psychosis. PMD with non-psychotic depression were apparently less severe than MD patients and had a lower rate of "non-responders" to AD treatment. Sub-threshold manic symptoms and suicidal risk were also more pronounced among PMD.
LIMITATIONS: The lack of information about number and polarity of previous psychotic mood episodes may be the major limitations of our study.
CONCLUSIONS: BP diagnosis is the most significant predictor for psychosis in mood disorders. Non-psychotic mood episodes in PMD patients may be characterized by a distinctive symptom profile and, possibly, a different response to treatment.