Brain maturation may be arrested in chronic cocaine addicts.

BACKGROUND Animal and human newborn studies suggest that exposure to cocaine in utero delays glial maturation and white matter myelination. Postmortem data show that in the frontal and temporal lobes, white matter myelination continues into middle age. Recent magnetic resonance imaging (MRI) data have confirmed continued white matter volume increase in these regions, reaching a maximum at age 47. METHODS Thirty-seven male cocaine dependent (CD) and 52 normal control subjects between ages 19 and 47 were evaluated with MRI. Coronal images focused on the frontal and temporal lobes were acquired using pulse sequences that maximized gray/white matter contrast. RESULTS Highly significant positive correlations between white matter volume and age were observed in both the frontal and temporal lobes of the control group (r =.52, p =.0001 and r =.54, p =.0001, respectively); however, CD subjects did not demonstrate any age-related increase in white matter volume of the frontal (r = -.001; p =.99) and temporal (r = -.07; p =.67) lobes in this age range. CONCLUSIONS The age-related expansion in white matter volume occurring in normal control subjects was absent in CD subjects. The findings suggest that in adults, cocaine dependence may arrest normal white matter maturation in the frontal and temporal lobes of addicts who continue using cocaine.