Altered striatal dopamine re-uptake site densities in habitually violent and non-violent alcoholics

Animal studies suggest that development of substance dependence is associated with dopaminergic activity in striatum and the limbic system. Several genetic studies indicate that allele A1 is associated with both D2 receptor density and alcoholism, although these findings have remained controversial. We studied striatal dopamine (DA) re-uptake site densities in 48 subjects (19 healthy controls, 19 habitually impulsive violent alcoholics, and 10 non-violent alcoholics) with single photon emission computed tomography (SPECT) using iodine-123-labelled 2 beta-carbomethoxy-3 beta(4-iodophenyl)tropane, (beta-CIT) as a tracer. Blind quantitative analysis revealed that the striatal DA transporter density was markedly lower in non-violent alcoholics than in healthy controls (P < 0.001), while violent alcoholics had slightly higher DA transporter densities than controls (P < 0.10). The results indicate that both types of alcoholics have alterations in striatal dopaminergic system, though these occur in opposite directions.