Comorbidity of obsessive-compulsive disorder and personality disorders. A Brazilian controlled study

The aim of this study was to evaluate the presence of personality disorders (PDs) in 40 patients with obsessive-compulsive disorder (DSM-III-R criteria) from the Medical School of Botucatu (UNESP), São Paulo, Brazil. It is a case-control study. Patients were 24 women and 16 men, 16-68 years old, referred to our outpatient psychiatric service for treatment. Controls were 40 nonpsychiatric outpatients matched to the cases by sex, age and marital status. The instrument used was the Portuguese version of the Structured Interview for DSM-III-R Personality Disorders (SIDP-R). All interviews (n = 80) were made simultaneously by 2 raters, with independent scoring, so that the interrater reliability of the instrument could also be assessed (kappa statistics). The consensual axis II diagnoses in the OCD group were: avoidant (52.5%, kappa = 0.80), dependent (40%, kappa = 0.84), histrionic (20%, kappa = 0.83), paranoid (20%, kappa = 0.74), obsessive-compulsive (17.5%, kappa = 0.86), narcissistic (7.5%, kappa = 1.00), schizotypal (5%, kappa = 0.65), passive-aggressive (5%, kappa = 0.79) and self-defeating (5%, kappa = 0.55). At least one PD diagnosis was made in 70% of the patients, while only 6 controls had a PD diagnosis (p < 0.01). A great deal of diagnostic overlap was found in the OCD group (57.5% had two or more PDs), especially between avoidant and dependent PDs. The features of these two PDs may be secondary to the OCD. The study also suggests that there is not a close relationship between OCD and obsessive-compulsive personality disorder (OCPD). Patients with OCPD or even 3 or 4 O-C traits had significantly less insight into their obsessions and compulsions (p < 0.01).