2010/11/20 by Nora T. Walter, Christian Montag, Sebastian A. Markett +2
Medicine · Psychology · #Psychosomatic Disorders and Their Treatments #Fibromyalgia and Chronic Fatigue Syndrome Research #Obsessive-Compulsive Spectrum Disorders
paper · doi:10.1097/psy.0b013e31820037c1
Objective: To test the hypothesis that the interaction between the brain-derived neurotrophic factor (BDNF) and dopamine receptor D2 (DRD2)/ANKK1 gene contributes to individual differences in alexithymia. The personality construct of alexithymia refers to difficulties in emotional self-regulation and contributes as a risk factor to several mental disorders. Alexithymic individuals show an impoverished conscious experience of emotions but an intact autonomic emotional response. Persons with high alexithymia scores reportedly show a reduced activation of the anterior cingulate cortex (ACC) during the processing of emotional stimuli. An interaction between two polymorphisms on the BDNF and DRD2/ANKK1 gene has been recently associated with reduced gray matter volume in the ACC and higher trait anxiety. Methods: We conducted a genetic association study. A total of 664 healthy participants completed the Toronto Alexithymia Scale questionnaire and were genotyped for the BDNF Val66Met (rs6265) and the DRD2/ANKK1 Taq IA (rs1800497) polymorphisms. Results: Carriers of at least one BDNF 66Met and one DRD2/ANKK1 A1 allele showed the highest scores in the total Toronto Alexithymia Scale and in the subscale “Difficulties Identifying Feelings.” Conclusion: In line with recent studies investigating the role of BDNF Val66Met and DRD2/ANKK1 Taq IA polymorphisms on anxiety and gray matter volume in the ACC, our findings provide the first evidence for a genetic contribution to alexithymia. ACC = anterior cingulate cortex; TAS-20 = Toronto Alexithymia Scale; DIF = TAS-20 subscale Difficulties Identifying Feelings; DDF = TAS-20 subscale Difficulties Describing Feelings; EOT = TAS-20 subscale Externally Oriented Thinking; BDNF = brain-derived neurotrophic factor; DRD2 = dopamine receptor D2; CBF = cerebral blood flow; TCI = Temperament and Character Inventory; VTA = ventral tegmental area; PD = panic disorder.