Prefrontal cortical volume reduction associated with frontal cortex function deficit in 6-week abstinent crack-cocaine dependent men

Abstract

Background-This study examined regional cortical volumes in 6-week abstinent men dependent on crack-cocaine only (Cr) or on both crack-cocaine and alcohol (CrA). Our goal was to test the a priori hypothesis of prefrontal cortical volume reduction, along with associated impairments in frontal mediated functions, and to look for differences between the Cr and CrA groups.Methods-Structural magnetic resonance imaging (MRI) of the brain and neuropsychological assessment were performed on 17 6-week abstinent Cr subjects, 29 six-week abstinent CrA subjects, and 20 normal controls. Cortical volume was quantified in the prefrontal, parietal, temporal and occipital regions.Results-Cr and CrA subjects showed comparable reductions in prefrontal gray matter volume compared to controls; this reduction was negatively associated with performance impairments in the executive function domain.Conclusions-Dependence on Cr (with or without concomitant alcohol dependence) was associated with reduced prefrontal cortical volume. Cr dependence with concomitant alcohol dependence was not associated with greater prefrontal volume reductions than Cr dependence alone. The existence of these findings at 6-week abstinence indicates that they are not a result of acute cocaine or alcohol exposure. The association of reduced prefrontal cortical volume with cognitive impairments in frontal cortex mediated abilities suggests that this reduced cerebral volume has functional consequences.

Brain macrostructural and microstructural abnormalities in cocaine dependence

“…Although other investigators employing DTI have found WM microstructural abnormalities in patients with chronic alcohol abuse Sullivan, 2002, 2005), the alcohol use in those samples was substantially higher than in the current study. Likewise, a direct comparison of cocaine users and cocaine + alcohol users has been published, and this study showed no significant differences in prefrontal volumes (Fein et al, 2002). Ultimately, a DTI study incorporating an alcohol-only control group will help to clarify the findings.…”

“…Recent magnetic resonance (MR) imaging studies have provided strong evidence that cocaine abuse is associated with structural brain abnormalities in both gray matter (GM) and white matter (WM) (Bartzokis et al, 2002;Fein et al, 2002;Franklin et al, 2002;Lim et al, 2002;Moeller et al, 2005). Evidence from functional neuroimaging studies and investigations of neuropsychological deficits also point to long-term changes in brain status associated with cocaine abuse (Bolla et al, 2000;Goldstein et al, 2004;Volkow et al, 2005).…”

Neuropsychological Complications of HIV Disease and Substances of Abuse

“…Research with cocaine users has found cognitive impairments in the areas of attention, learning, memory, executive functions and cognitive flexibility [17][18][19][20][21][22] . These effects are also present among those who consume the drug in its smokeable form--crack cocaine--and may be even more pronounced in these users compared to cocaine users who do not smoke the drug [23][24][25][26] . Methamphetamine usage has been reported to be associated with the impairment of dopamine function (even after several years of discontinuance) and is known to affect several brain functions, including pleasure, mood and movement.…”

Animal models of drug addiction: Where do we go from here?

“…As well, increases in monoamine transporters in the orbitofrontal cortex (Little et al, 1998), reductions in grey matter density in orbitofrontal and cingulate cortices (Franklin et al, 2002), and reduced functional activity in the ventromedial PFC (Hommer et al, 1997;London, Ernst, Grant, Bonson, & Weinstein, 2000;Stapleton et al, 1995;Volkow & Fowler, 2000) are evident following long-term cocaine use. Structural changes in the PFC of addicts correlate with functional deficits, and both are apparent up to 6 weeks into abstinence (Fein, Di Sclafani, & Meyerhoff, 2002). Importantly, at least some drug addicts exhibit deficits in a decision-making task known to be sensitive to PFC damage (Bechara & Damasio, 2002).…”