Association between the Catechol-O-Methyltransferase (COMT) Val(158)Met Polymorphism and Alexithymia in Patients with Obsessive-Compulsive Disorder

PURPOSE: Alexithymia, defined as a deficit in the ability to recognize and describe one's own feelings, may be related to the development and maintenance of obsessive-compulsive symptoms. The aim of this study was to evaluate the association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and alexithymia in patients with obsessive-compulsive disorder (OCD). MATERIALS AND METHODS: We recruited 244 patients with OCD (169 males, 75 females). Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20), and genotyping of the COMT Val(158)Met polymorphism was evaluated. RESULTS: Patients with the COMT Val/Val genotype had significantly higher total and "difficulty identifying feelings" (DIF) subdimension scores than those with the Val/Met or Met/Met genotypes. Patients with the COMT Val/Val genotype had significantly higher "difficulty describing feelings" (DDF) subdimension scores than those with the COMT Val/Met genotype. However, there were no differences in the scores for the "externally oriented thinking" (EOT) subdimension among the three genotypes. CONCLUSION: These results indicate that the high-activity Val allele of the COMT Val(158)Met polymorphism is associated with increased alexithymic traits in patients with OCD. The present finding suggests that alexithymia is an endophenotype of OCD that is mediated by the COMT Val(158)Met polymorphism.

Reliability and Validity of the 20-Item Toronto Alexithymia Scale in Korean Adolescents

OBJECTIVE: Adolescence is a period of developing emotional regulation. However, alexithymia has rarely been examined during this period. The objective of this study is to examine the factor structure and internal consistency of the Korean version of the 20-item Toronto Alexithymia Scale (TAS-20K) in normal adolescents in South Korea. METHODS: The TAS-20K was administered to a sample of 290 adolescents aged from 12 to 16 years old. Internal reliability, test-retest reliability, and factorial validity were evaluated. RESULTS: The three factors of the TAS-20K were confirmed by confirmatory factor analysis. The internal consistency, measured using Cronbach's alpha coefficient was acceptable for difficulty in identifying feelings, good for difficulty in describing feelings, and acceptable for externally oriented thinking. CONCLUSION: Our study indicates that the TAS-20K is an appropriate instrument to assess alexithymia in Korean adolescents.

The Relationship between Alexithymia and General Symptoms of Patients with Depressive Disorders

OBJECTIVE: Depression has been associated with alexithymic features. However, few studies have investigated the differences in the general symptoms of patients with depressive disorders according to the presence of alexithymia. Thus, the aim of this study was to evaluate the relationship between alexithymia and symptoms experienced by patients with clinically diagnosed depressive disorders. METHODS: A chart review of patients who were evaluated using the Korean version of the 20-item Toronto Alexithymia Scale (TAS-20) and Symptom Checklist 90-Revised (SCL-90-R) at the same time between the years 2003 and 2007 was conducted. A total of 104 patients with depressive disorders were included and divided into two groups: alexithymia (n=52) and non-alexithymia (n=52). A direct comparison between the two groups was carried out. Regression analysis was also carried out for the TAS-20 total and subset scores in order to model the relationship between alexithymia and symptoms. RESULTS: The presence of alexithymia was confirmed in 50% of the patients with depressive disorders, and the symptoms of depressive patients with alexithymia were more severe than those of their non-alexithymic counterparts on all 9 symptom domains of the SCL-90-R. Furthermore, regression analysis revealed that the presence of alexithymia was positively associated with depression, phobic anxiety, and psychoticism but inversely associated with anxiety. CONCLUSION: These results suggest that the clinical features of depression are partially dependent on the presence of alexithymia. Alexithymic patients with depressive disorders are likely to show more severe depressive, psychotic, and phobic symptoms. In other words, clinicians should suspect the presence of alexithymic tendencies if these symptoms coexist in patients with depressive disorders and address their difficulties in effective communication.