Obsessive-compulsive disorder and personality disorder: evidence from the British National Survey of Psychiatric Morbidity 2000.

BACKGROUND: Previous studies indicate that most individuals with obsessive-compulsive disorder (OCD) have comorbid personality disorders (PDs), particularly from the anxious cluster. However, the nature and strength of this association remains unclear, as the majority of previous studies have relied heavily on clinical populations. We analysed the prevalence of screen positive personality disorder in a representative sample of adults with OCD living in private households in the UK.
METHODS: A secondary analysis of data from the 2000 British National Survey of Psychiatric Morbidity. The prevalence of PD, as determined by the SCID-II questionnaire, was compared in participants with OCD, with other neuroses and non-neurotic controls. Within the OCD group we also analysed possible differences relating to sex and subtypes of the disorder.
RESULTS: The prevalence of any screen positive PD in the OCD group (N=108) was 74%, significantly greater than in both control groups. The most common screen positive categories were paranoid, obsessive-compulsive, avoidant, schizoid and schizotypal. Compared to participants with other neuroses, OCD cases were more likely to screen positively for paranoid, avoidant, schizotypal, dependent and narcissistic PDs. Men with OCD were more likely to screen positively for PDs in general, cluster A PDs, antisocial, obsessive-compulsive and narcissistic categories. The presence of comorbid neuroses in people with OCD had no significant effect on the prevalence of PD.
CONCLUSIONS: Personality pathology is highly prevalent among people with OCD who are living in the community and should be routinely assessed, as it may affect help-seeking behaviour and response to treatment.