Decreased GABA concentrations in left prefrontal cortex of methamphetamine dependent patients: A proton magnetic resonance spectroscopy study

Abstract

Increasing evidence suggested the dorsolateral prefrontal cortex (DLPFC) is implicated in the pathogenesis of methamphetamine use disorder. Metabolites changes of DLPFC may mediate the progression of addiction. We used proton magnetic resonance spectroscopy (1H-MRS) to examine the changes of metabolites in the left DLPFC in individuals with methamphetamine dependence compared to healthy controls. Fifty patients and twenty age-matched healthy controls participated in this study. The 1H MRS data were automatically fit with linear combination model for quantification of metabolite levels of γ-aminobutyric acid (GABA), glutamate + glutamine (Glx) and other metabolites across groups. The GABA and Glx levels were calculated with the unsuppressed water signal as reference. Methamphetamine users showed reduced GABA and GABA/Glx in left DLPFC than healthy controls. Furthermore, the concentration of GSH, GPC, Ins, NAA, GPC + PCh, NAA + NAAG, Cr + PCr were lower in individuals with methamphetamine dependence compared with controls. The patients group's relative GABA and Glx metabolite concentrations were significantly correlated with age and duration of withdrawal. Our preliminary findings provide the first report of abnormal levels of GABA in left DLPFC of patients with methamphetamine use disorder, indicating that dysregulation of the GABAergic neurotransmitter system may be an important neurobiological mechanism in the pathogenesis of methamphetamine dependence.