Obsessive-compulsive spectrum disorders and rheumatic fever: a family study.

BACKGROUND: Obsessive-compulsive spectrum disorders (OCSDs) are more frequent in patients with active or prior rheumatic fever (RF), suggesting that OCSD and RF may share underlying etiologic mechanisms. Our objective was to estimate the frequency of OCSD in first-degree relatives (FDRs) of RF patients and controls to determine whether there is a familial relationship between OCSD and RF. METHODS: This is a case-control family study. Of the 98 probands included in this study, 31 had RF without Sydenham's chorea (SC) and had 131 relatives, 28 had RF with SC and had 120 relatives, and 39 were controls without RF. All probands, 87.9% of the RF FDRs and 93.7% of the control FDRs were assessed directly with structured psychiatric interviews and best-estimate diagnoses were assigned. Odds ratios of morbid risks were estimated using logistic regression by the generalized estimating equations (GEE) method and compared between groups. RESULTS: The rate of OCSDs was significantly higher among FDRs of RF probands than among FDRs of controls (n=37; 14.7% vs. n=10; 7.3%, i=.0279). A diagnosis of OCSDs in an RF proband was associated with a higher rate of OCSDs among FDRs when compared to control FDRs (p-GEE=.02). There was a trend for a higher rate of OCSDs among FDRs of RF probands presenting no OCSD, although the difference was not significant (p-GEE=.09). CONCLUSION: The results are consistent with the hypothesis that a familial relationship exists between OCSD and RF, since an OCSD in the RF proband was found to increase the risk of OCSDs among FDRs. Additional neuroimmunological and genetic studies involving larger samples are needed to further elucidate this apparent familial relationship between RF and OCSD.

A family study of early-onset obsessive-compulsive disorder.

Results from family studies have suggested that obsessive-compulsive disorder (OCD) is a genetically heterogeneous disorder and have emphasized the importance of identifying valid subgroups of patients. The current study focused on early-onset OCD probands and examined the recurrence risks of OCD and tics among first-degree family members. One hundred six children and adolescents with OCD were recruited from a specialty clinic for OCD and 44 control individuals without OCD were identified by random-digit dialing. These 150 probands and their 465 first-degree relatives were assessed by trained interviewers, using standardized semi-structured interviews. Diagnoses were assigned according to DSM-IV criteria by two experts blind to the proband's diagnosis, through the best-estimate process. These data were analyzed using chi(2) tests, t-tests, logistic regression, and generalized estimating equations (GEE). Case probands had a mean age of onset of OC symptoms of 6.7 years (SD = 2.8), and high comorbid rates with Tourette syndrome (33%) and chronic tics (13.2%). Compared to control relatives, case relatives had higher age-corrected recurrence risks of OCD (22.7% vs. 0.9%, odds ratio (OR) = 32.5, 95% confidence interval (CI) = 4.5-230.8, P = 0.0005), and chronic tics (11.6% vs. 1.7%, OR = 7.9, 95% CI = 1.9-33.1, P = 0.005). A comorbid diagnosis of tics in the relatives was the best predictor of their diagnosis of OCD (OR = 7.35, 95% CI = 3.79-14.25, P < 0.0001). There was a significant correlation between the ages of onset of OCD in probands and their affected relatives. Childhood onset OCD is a highly familial disorder. Some early-onset cases may represent a valid subgroup, with higher genetic loading and shared vulnerability with chronic tic disorders.