Effect of prodynorphin (PDYN) RS910080 polymorphism on depressive symptoms in alcohol use disorder

Alcohol use disorder is a chronic and recurrent brain disorder due to environmental and genetic factors. It is characterized by intense cravings for alcohol consumption, loss of control over alcohol consumption, and negative moods during abstinence. According to the data of the World Health Organization, deaths as a result of alcohol consumption in 2012 constitute 5.9% of the total deaths worldwide. It is known that aggression increases in individuals with alcohol use disorder, and their decision-making ability decreases, and thus they become prone to crime. One of the genes investigated in studies to determine the genetic effects of alcohol use disorder is PDYN. In some of these studies, a significant relationship was observed between PDYN gene polymorphisms and susceptibility to alcohol dependence. The PDYN gene encodes dynorphins that bind to kappa opioid receptors, and dynorphins are known to cause depressive effects together with their receptors. Therefore, in this master thesis study, it was aimed to investigate the effect of PDYN rs910080 polymorphism on depressive symptoms in individuals diagnosed with alcohol use disorder in Turkey. Male individuals diagnosed with alcohol use disorder (n=100) who were treated in the Department of Mental Health and Diseases of Ankara University Faculty of Medicine were included in the study. The depressive symptoms of the patients were determined using the Beck Depression Inventory-II. The PDYN rs910080 gene polymorphism was determined by the Polymerase Chain Reaction (PCR=Polymerase chain reaction)-Restriction Fragment Length Polymorphism (RFLP=Restriction Fragment Length Polymorphism) method. The allele frequencies determined for the PDYN rs910080 polymorphism were 66% (n:132) for the A allele and 34% (n:68) for the G allele. The mean depressive scores of the participants in the study were 22.66±11.75 (0-49). Depression scale scores were compared according to PDYN 910080 polymorphism genotypes and no significant relationships were observed between the PDYN rs910080 genotypes and the severity of depressive symptoms according to the co-dominant, A-dominant and A-recessive models (p=0.674; p=0.443; p=0.525, respectively). However, depressive symptom severity of individuals with AA genotype (23.56±11.17) was found to be higher than that of individuals with GG genotype (19.78±11.92). In conclusion, it was observed that PDYN 910080 polymorphism may have an effect on depressive symptoms in Turkish individuals with alcohol use disorder. It was thought that further studies involving more individuals are needed to support our findings.