TPH2 gene variants and anxiety during alcohol detoxification outcome

Clinical outcome of alcoholism may be partly under genetic control. The serotonergic system is involved in alcohol intake, and it has been widely investigated in alcohol dependence. Recently, attention has been focused on the neuronal tryptophan hydroxylase 2 gene (TPH2). TPH2 variants have been consistently associated with anxiety-related traits; since anxiety is critical for alcohol dependence treatment, in the present paper we investigated 9 SNPs within the THP2 gene in anxiety symptoms during the detoxification procedure. The sample comprised 68 alcohol-dependent patients who where evaluated with the Hamilton Rating Scale for Anxiety, before and after the detoxification procedure. Other psychopathological indicators of outcome, such as depression and anxiety sub-features were also investigated. We did not observe a role for TPH2 variants in the efficacy of treatment in relieving anxiety and other psychopathological symptoms. However, a haplotype that included the promoter rs4570625 polymorphism (associated with anxiety-related traits in previous studies) showed an association with the severity of anxiety symptoms on admission. This preliminary finding, although obtained on a small sample, may provide further support for a role of the TPH2 gene in emotional behaviors. Furthermore, the present study suggests the possible functional significance of the promoter rs4570625 polymorphism. The present preliminary results are of interest in alcoholism, given that comorbidity with anxiety represents a critical problem in treatment settings and response to detoxification. (C) 2007 Elsevier Ireland Ltd. All rights reserved.