Reduced volume of the nucleus accumbens in heroin addiction.

Christian L Seifert,Stefano Magon,André Schmidt,Ernst-Wilhelm Radue,Marc Vogel,Marc Walter,Undine E Lang,Christian G Huber,Niklaus Denier,Stefan Borgwardt,Till Sprenger

doi:10.1007/s00406-014-0564-y

Abstract

The neural mechanisms of heroin addiction are still incompletely understood, even though modern neuroimaging techniques offer insights into disease-related changes in vivo. While changes on cortical structure have been reported in heroin addiction, evidence from subcortical areas remains underrepresented. Functional imaging studies revealed that the brain reward system and particularly the nucleus accumbens (NAcc) play a pivotal role in the pathophysiology of drug addiction. The aim of this study was to investigate whether there was a volume difference of the NAcc in heroin addiction in comparison to healthy controls. A further aim was to correlate subcortical volumes with clinical measurements on negative affects in addiction. Thirty heroin-dependent patients under maintenance treatment with diacetylmorphine and twenty healthy controls underwent structural MRI scanning at 3T. Subcortical segmentation analysis was performed using FMRIB's Integrated Registration and Segmentation Tool function of FSL. The State-Trait Anxiety Inventory and the Beck Depression Inventory were used to assess trait anxiety and depressive symptoms, respectively. A decreased volume of the left NAcc was observed in heroin-dependent patients compared to healthy controls. Depression score was negatively correlated with left NAcc volume in patients, whereas a positive correlation was found between the daily opioid dose and the volume of the right amygdala. This study indicates that there might be structural differences of the NAcc in heroin-dependent patients in comparison with healthy controls. Furthermore, correlations of subcortical structures with negative emotions and opioid doses might be of future relevance for the investigation of heroin addiction.

Highlights

Drug addiction including heroin dependence was investigated in a number of neuroimaging studies, which have repeatedly shown that drug-induced changes of brain structure and function have contributed to impairments in cognitive and emotional processes [4, 10, 24]
Liu et al [21] published a voxel-based morphometry (VBM) study, in which heroin-dependent patients showed reduced grey matter volumes in the right prefrontal cortex (PFC), anterior cingulate cortex (ACC) and the left supplementary motor area when compared to healthy controls
We aimed to examine whether the volume of the nucleus accumbens (NAcc) differed between heroindependent patients and healthy controls using an automatic subcortical segmentation method

Summary

Introduction

Drug addiction including heroin dependence was investigated in a number of neuroimaging studies, which have repeatedly shown that drug-induced changes of brain structure and function have contributed to impairments in cognitive and emotional processes [4, 10, 24]. Liu et al [21] published a VBM study, in which heroin-dependent patients showed reduced grey matter volumes in the right PFC, ACC and the left supplementary motor area when compared to healthy controls. Another VBM study demonstrated a correlation of the duration of heroin use with decreased grey matter densities in prefrontal, temporal and cingulate cortices [58]. At least one multimodal neuroimaging study revealed a decreased volume of the amygdala in ten opioid-addicted patients in comparison with healthy controls, but no change in the NAcc [46]

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