The psychotic spectrum: a community-based study.

Over the last years, there has been an increasing awareness and knowledge about bipolar spectrum disorders. However, descriptive data on bipolar I disorder with psychotic features (BPI-p) in comparison with schizophrenia (SCH) and schizoaffective disorder (SA) in mental health community services are scanty in the literature. We conducted a study with the aim of assessing the prevalence, clinical characteristics and levels of functioning of SCH, SA and BPI-p in a random sample of patients with psychotic symptoms recruited in nine departments of mental health. Patients with a psychotic disorder according to their treating clinicians were assessed using the SCID and a series of questionnaires to evaluate their psychopathology and level of functioning. Patients who received a DSM-IV diagnosis of SA (N=55), SCH (N=82), or BPI-p (N=60) represented the final sample. The three diagnostic groups showed similar demographic characteristics. Independently from the diagnosis, all patients had a long duration of illness and a persistent course. Uni-variate group comparisons showed that, as compared to SCH patients, BPI-p and SA patients did better in several measures of functioning and differed in frequency of psychotic symptoms. However, a multinomial logistic regression model in which only significantly different variables were entered showed similar levels of functioning in the three groups of patients. The three groups' scores did not significantly differ on instruments that assessed dimensionally psychotic and affective symptoms during the previous month.