Despite the growing literature on the co-occurrence of obsessive-compulsive disorder (OCD) and schizophrenia, there is a lack of studies addressing the co-occurrence of OCD spectrum disorders, such as hypochondriasis, and schizophrenia.

The aim of the study was to investigate the prevalence rates of OCD and Hypochondriasis in schizophrenic patients treated with clozapine versus other atypical antipsychotics (AAPs).

We enrolled 24 consecutive schizophrenic patients treated with clozapine attending the ‘Clozapine Clinic’ of the University of Florence and 24 consecutive schizophrenic patients treated with other AAPs. Patient’s assessment was performed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Hypochondriasis Y-BOCS (HY-BOCS) and the Global Assessment of Functioning Scale (GAF).

Considering the whole group (n = 48), we found an OCD prevalence rate of 29.2% (n = 14) and a hypochondriasis prevalence rate of 22.9% (n = 11). We found a significant correlation between Y-BOCS and HY-BOCS scores (p = .007) suggesting an association between OCD and hypochondriasis in these patients. We also found a significant negative correlation between H-YBOCS scores and GAF scores (p = .006). Clozapine-treated patients had a higher rate of OCD (37.5% vs 20.8%). and hypochondriasis (37.5% vs 8.3%) than other AAP-treated patients.

We found a higher prevalence rate of OCD and hypochondriasis comorbidity in schizophrenic patients than in general population. The prevalence rate of OCD and hypochondriasis was higher in clozapine-treated patients versus other AAP-treated patients. Furthermore, the severity of hypochondriasis symptoms was correlated to a lower level of global functioning.