The current paper was aimed at: (1) investigating the comorbidity between obsessive-compulsive disorder (OCD) and personality disorders (PDs) using an OCD sample and clinician-administered structured interviews; (2) exploring the associations of different cluster comorbid PDs with the specific symptom dimensions of OCD; (3) analyzing the variables which could play a significant role in the probability of having at least one comorbid PD, controlling for confounding variables. The SCID-II and Y-BOCS, together with a series of self-report measures of OCD, depression and anxiety symptoms were administered to a clinical sample of 159 patients with a primary diagnosis of OCD. 20.8 % of the participants suffered from at least one comorbid PD; the most common was obsessive-compulsive PD (9.4 %), followed by narcissistic PD (6.3 %). In OCD patients with comorbid cluster C PDs, the percentage of responsibility for harm, injury, or bad luck symptoms was significantly greater than other OCD symptom dimensions (p < .005). Logistic regression found some evidence supporting the association between severity of OCD symptoms and comorbid PDs. PDs are prevalent among Italian people with OCD and should be routinely assessed, as comorbidity may affect help-seeking behaviour and response to treatment.
Keywords: Comorbidity; OCD symptom dimensions; Obsessive–compulsive disorder; Personality disorders; Prevalence.