Personality disorders in obsessive compulsive disorder.

Standardized structured interview personality scales are now available that provide better reliability than clinician interview, but are still imperfect. These scales diagnose DSM III-R personality disorders, which are more illness-oriented than Freudian notions. Use of these scales has found that the majority of patients with OCD have at least one Axis II personality disorder, with most falling in cluster C. Obsessive compulsive personality disorder, as described in DSM-III-R, is, in most samples studied, present in the minority of patients with OCD, and is often less common than other personality disorders such as mixed, dependent, avoidant, and histrionic. The prevalence of this personality disorder as modified in DSM-III-R (making it easier for a patient to qualify for this personality disorder diagnosis) appears to be higher, although still present in a minority of patients with OCD. Obsessive compulsive personality disorder (along with the other cluster B and C personality disorders) has not been reported to have a consistent relation to treatment outcome. There is evidence that in some cases, obsessive compulsive personality disorder may be secondary to OCD. Swedo et al hypothesized that some children may develop compulsive personality traits as an adaptive mechanism to deal with OCD. This hypothesis is in accord with our finding that OCD often predates compulsive personality disorder and that mixed personality disorder may develop over time, possibly secondary to OCD. We found in our sample of 96 adult patients with OCD that the presence of mixed personality disorder was more likely with longer duration of OCD, suggesting that patients who do not have premorbid personality disorders may develop significant personality traits (especially avoidant, compulsive, and dependent), which may be related to behavioral and life-style changes that are secondary to OCD. This hypothesis is strengthened by our finding that patients with one of these personality disorders at baseline tended to no longer meet criteria for them following successful treatment of their OCD. It now appears that schizotypal personality disorder, which is thought to be related genetically to schizophrenia (e.g., in three male identical twin pairs concordant for OCD but discordant for schizophrenia or schizoaffective disorder, the nonpsychotic co-twins all had schizotypal personality disorder), is the only consistent personality disorder predictor of poorer outcome in OCD. These traits may help explain other proposed poor predictors of treatment outcome such as overvalued beliefs, poor compliance, and chaotic family situations.(ABSTRACT TRUNCATED AT 400 WORDS)