Schizophrenia and co-morbid obsessive - compulsive disorder: Clinical characteristics

Psychiatric co-morbidity is a common condition, partly due to the overlap of symptoms in the categorical diagnosis of mental disorders. The co-occurrence of schizophrenia (SZ) and obsessive compulsive disorder (OCD) is a common and challenging co-morbid condition. Also, the relationship between SZ and OCD remains unclear.

The aim of this study was to describe the co-morbidity of obsessive-compulsive disorder (OCD) among schizophrenia (SZ) patients and compare clinical characteristics of schizophrenia patients with versus without comorbid OCD.

A cohort-study was carried out on 396 patients enrolled between November 2011 to June 2014 at the Department of Psychiatry, Rumeilah Hospital in Qatar. We employed the WHO Composite International Diagnostic Interview (WHO-CIDI), and Structured clinical interview for DSM-5 (SCID-5) for diagnoses, the Yale-Brown Obsessive Compulsive Scale Symptom Checklist for scoring OCD. Patients were grouped in SZ patients with and without comorbid OCD (SZ-OCD vs SZ).

396 subjects were interviewed. Age of SZ-OCD patients was 42.69 ± 14.33 (years old) whereas SZ patients without OCD ranged 41.59 ± 13.59 years old. There were statistically significant differences in clinical characteristics between SZ with and without OCD : age (p = 0.010), BMI (body mass index; p = 0.011), education (p = 0.033), employment (p = 0.019), cigarette smoking (p = 0.039), sheesha smoking (p = 0.008), and prevalence of consanguinity (p = 0.043). In particular, the rate of consanguinity in the current generation was 31.8% [95% CI = 29.1-34.7]. Also, there were statistically significant differences at Hamilton Depression score, General Health Score, Clinical Global Impression- Score, duration of illnesses, and Global Assessment of Functioning (p < 0.001). The results show that anxious, mood and psychotic dimensions rated higher among SZ - OCD ones than SZ only patients.

This study confirms that SZ-OCD is a common co-morbidity and prevalence of SZ OCD is higher among patients reporting a degree of consanguinity. Even if this condition is under-recognized in clinical practice, it may significantly change SZ presentation and outcome since psychopathological dimensions report higher scores in the co-morbidity sample.