Objective: To explore the genetic etiology of obsessive-compulsive disorder (OCD) and genetic association between OCD and tic disorder.
Methods: The mental disorders in the first degree and second degree relatives of 90 probands with OCD were investigated and compared with those of 100 healthy families by the method of family genetic study.
Results: Compared to the control, the prevalence rates of schizophrenia, affective disorder, minor depression, subclinical OCD, general anxiety disorder and tic disorder in the first degree relatives of OCD were elevated, except that of OCD. The prevalence rates of OCD and subclinical OCD, general anxiety disorder, and other neurotic disorders in the first degree relatives of patients with pure obsession were 47.6%, 35.7% and 23.8%, respectively; compared to 10.8%, 3.6% and 0 in those of the control (P<0.01). The prevalence rates of schizophrenia,affective disorder,and tic disorder in the first degree relatives of OCD with tic were 52.0%, 26.0% and 90.9%, respectively; compared to 0, 3.6% and 7.2% in those of the control (P<0.01).
Conclusion: The etiology of OCD is related to heredity. There was evidence to show genetic association between OCD and tic disorder,The elevation of prevalence rates of various mental disorders in the first degree relatives of OCD might suggest the genetic basis of various subtypes of OCD.