Reduced Frontal Brain Volume in Non-Treatment-Seeking Cocaine-Dependent Individuals: Exploring the Role of Impulsivity, Depression, and Smoking

Cleo L Crunelle,Wim Van Den Brink,Hanna E Van Den Munkhof,Anne Marije Kaag,Guido Van Wingen,Judith R Homberg,Liesbeth Reneman

doi:10.3389/fnhum.2014.00007

Abstract

In cocaine-dependent patients, gray matter (GM) volume reductions have been observed in the frontal lobes that are associated with the duration of cocaine use. Studies are mostly restricted to treatment-seekers and studies in non-treatment-seeking cocaine abusers are sparse. Here, we assessed GM volume differences between 30 non-treatment-seeking cocaine-dependent individuals and 33 non-drug using controls using voxel-based morphometry. Additionally, within the group of non-treatment-seeking cocaine-dependent individuals, we explored the role of frequently co-occurring features such as trait impulsivity (Barratt Impulsivity Scale, BIS), smoking, and depressive symptoms (Beck Depression Inventory), as well as the role of cocaine use duration, on frontal GM volume. Smaller GM volumes in non-treatment-seeking cocaine-dependent individuals were observed in the left middle frontal gyrus. Moreover, within the group of cocaine users, trait impulsivity was associated with reduced GM volume in the right orbitofrontal cortex, the left precentral gyrus, and the right superior frontal gyrus, whereas no effect of smoking severity, depressive symptoms, or duration of cocaine use was observed on regional GM volumes. Our data show an important association between trait impulsivity and frontal GM volumes in cocaine-dependent individuals. In contrast to previous studies with treatment-seeking cocaine-dependent patients, no significant effects of smoking severity, depressive symptoms, or duration of cocaine use on frontal GM volume were observed. Reduced frontal GM volumes in non-treatment-seeking cocaine-dependent subjects are associated with trait impulsivity and are not associated with co-occurring nicotine dependence or depression.

Highlights

Impulsivity is an inherent feature of drug dependence and is closely related to frontal lobe function (Cho et al, 2013)
In non-treatment-seeking cocaine-dependent individuals, we investigate the relationship between frontal gray matter (GM) volume and self-reported impulsivity, comorbid nicotine use and the presence of depressive symptoms, and we investigate the relationship between duration of cocaine use and frontal GM volume
In non-treatment-seeking cocaine-dependent individuals compared to non-drug using healthy controls (HCs), significant GM volume reductions were found in the left middle frontal gyrus

Summary

Introduction

Impulsivity is an inherent feature of drug dependence and is closely related to frontal lobe function (Cho et al, 2013). Smaller gray matter (GM) volumes in frontal cortical areas (in the middle frontal gyri and the orbito- and dorso-lateral frontal cortices) have been repeatedly reported in cocaine-dependent individuals compared to non-drug users (Liu et al, 1998; O’Neill et al, 2001; Fein et al, 2002; Franklin et al, 2002; Matochik et al, 2003; Sim et al, 2007; Lim et al, 2008; Tanabe et al, 2009; Alia-Klein et al, 2011; Weller et al, 2011; Ide et al, 2013). The above mentioned studies were mainly performed in treatment-seeking cocaine-dependent patients (Fein et al, 2002; Franklin et al, 2002; Matochik et al, 2003; Tanabe et al, 2009; Barrós-Loscertales et al, 2011; Weller et al, 2011; Moreno-López et al, 2012; Ide et al, 2013) or in current cocaine abusers recruited via local advertisement or via unknown inclusion routes and without information regarding treatment-seeking status (Liu et al, 1998; Sim et al, 2007; Alia-Klein et al, 2011)

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Results

Conclusion