Psychopathology and quality of life among patients with comorbidity between schizophrenia spectrum disorder and obsessive-compulsive disorder: no evidence for a "schizo-obsessive" subtype.

Background: Epidemiological studies have found that obsessive-compulsive disorder (OCD) is estimated to occur in up to 12% of patients with schizophrenia. Furthermore, several etiopathogenic mechanisms have been postulated for understanding this co-occurrence. Whether this subgroup of "schizo-obsessive" patients may be posed as a clinical entity with a distinct psychopathological and functioning profile remains unclear.

Method: A sample of adult patients who met DSM-IV criteria for both schizophrenia/schizoaffective disorder and OCD (n=30) was compared with a "non-OCD schizophrenic" group (n=37) and another subset of "non-schizophrenic OCD" patients (n=30). The Positive and Negative Syndrome Scale (PANSS), the Scale to Assess Unawareness of Mental Disorder (SUMD), the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Brown Assessment of Beliefs Scale (BABS), the Clinical Global Severity scale (CGI), the Quality of Life Scale (QLS), and the Beck's Depression Inventory (BDI) were used.

Results: We found that "schizo-obsessive" subjects did not show significant differences in any outcome measures when compared to the "non-OCD schizophrenic" group. Furthermore, statistical analyses also revealed that the "non-schizophrenic OCD" group tended to have lower severity of psychopathology as well as greater quality of life than both psychotic groups.

Conclusions: These findings indicate that comorbidity between schizophrenia/schizoaffective disorder and OCD does not comprise a distinct clinical entity, particularly when compared to "non-OCD schizophrenia" disorder. Discrepancies among previous studies may be justified by methodological divergences.