Gamblers show white matter abnormalities similar to substance addicts
MedWire News: The brains of gambling addicts show white matter abnormalities comparable to those of substance abuse patients, say researchers.
A team led by Juho Joutsa from the University of Turku in Finland investigated the structural brain pathology of patients diagnosed with pathologic gambling addiction. They used magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), voxel-based morphometry (VBM) to measure regional brain volume, and tract based spatial statistics (TBSS) to measure white matter fiber connectivity.
Their study, published in the journal Psychiatry Research, involved 12 Caucasian men with pathologic gambling addiction and 12 healthy age-, race-, and gender-matched controls. Of the gamblers, seven reported being mainly addicted to slot machine gambling, two to internet poker, and three did not have a single preference.
The researchers found that the pathologic gamblers had widespread lower white matter integrity than the controls, as shown by significantly lower fractional anisotropy values and higher mean diffusivity, though not statistically significantly so. This was visible in a number of brain regions, namely the corpus callosum, the cingulum, the superior longitudinal fascicle, the inferior fronto-occipital fascicle, the anterior limb of internal capsule, the anterior thalamic radiation, the inferior longitudinal fascicle, and the uncinate/inferior fronto-occipital fascicle.
There were no significant differences in global cerebral volumes between the two study groups determined from the VBM analysis. Global white matter volume was significantly correlated with global mean fractional anisotropy values, but not with global mean diffusivity values.
The researchers say that the reduced integrity seen in various cerebral regions of the pathologic gambling patients has similarly been reported in patients with substance abuse disorders.
"The results of the present study, combined with the results of earlier studies with substance addictions, suggest a link between dysfunctional limbic white matter tracts and addiction disorders, in both chemical and behavioral addictions," say Joutsa and colleagues.
The participants in this study were screened for current substance abuse disorders and while three of the pathologic gambling patients had a history of alcohol dependence, exclusion of these participants did not influence the results. Therefore, the researchers say it is unlikely that their results were confounded by substance abuse effects.
No correlation was found between white matter integrity and severity or duration of gambling addiction.
"Further studies are needed to investigate what the exact microscopic differences in fiber tracts that cause the lower anisotropy are, what the functional long-term consequences of these changes are, and to investigate if the dysfunction in white matter axonal connections in [pathological gambling] is a predisposing factor or a consequence of the addiction," concludes the team.
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By Chloe McIvor