Association between Obsessive-Compulsive Disorder and Dopamine Transporter Gene Polymorphism

Abstract

Objective: The definite causes of obsessive-compulsive disorder (OCD) are still unknown. Recently, evidence has been growing that OCD has a specific neurochemical and neuroanatomical basis. The most prevailing biological mechanism of OCD is the serotonin hypothesis. However, in addition to this main hypothesis suggesting serotonin abnormalities, many researchers have proposed that dopamine might also participate in the pathophysiology of OCD. Therefore, the aim of this study was to investigate the association between dopamine transporter (DAT1) polymorphisms and OCD.

Methods: 115 OCD patients and 160 normal controls participated in this study. Genomic DNA was extracted from their blood, and a comparison of the genotypes and allele frequencies of the DAT1 polymorphism between the OCD group and control group was made. The genotypes of DAT1 are classified into 10/10-repeats and non-10/10 repeats.

Results: In this case-control study, there were no statistical differences in the observed genotype distributions or allele frequencies of the DAT1 polymorphism between these two groups. Moreover, there were no significant differences in the total Y-BOCS, CGI-OC, GAF or total HDRS scores between the patients with 10/10-repeat and non-10/10 repeat genotypes.

Conclusion: In conclusion, DAT1 polymorphisms do not appear to be associated with the development of OCD, the severity of OC or depressive symptoms, or the general functioning.