Further investigation of citalopram on alcohol consumption in heavy drinkers: responsiveness possibly linked to the DRD2 A2/A2 genotype

Abstract 

Citalopram, a selective serotonin reuptake inhibitor, has been suggested to reduce alcohol intake, at least in some studies. The present study aimed to replicate our earlier finding that citalopram reduces alcohol intake only in subjects with a weekly consumption ranging between 300 and 800 g of pure alcohol. Subjects (n=37) in this study were therefore randomized into a double-blind treatment with either 40 mg of citalopram daily or placebo for a 4-week period. Another purpose was to investigate whether different measures of central neurotransmission might predict an effect of citalopram or placebo on alcohol consumption. Therefore, prolactin response to d-fenfluramine, platelet monoamine oxidase-B activity, as well as the genotype of the dopamine D2 receptor (DRD2), A1 and A2 alleles, were determined and related to individual changes in alcohol consumption. Citalopram was not found to be superior to placebo in reducing alcohol intake. Prolactin responses to d-fenfluramine and levels of platelet monoamine oxidase-B activities were not related to changes in alcohol consumption, regardless of treatment with citalopram or placebo. When subjects were grouped according to the presence or absence of the DRD2 A1 allele, those with the genotype DRD2 A2/A2 were found to transiently reduce their alcohol consumption during citalopram treatment. This finding seems to indicate that, in subjects with heavy alcohol consumption, possession of the genotype DRD2 A2/A2 may be prerequisite for a treatment effect of citalopram.

Keywords:  Citalopram, Alcohol intake, Serotonin, DRD2