Prenatal cocaine exposure and gray matter volume in adolescent boys and girls: relationship to substance use initiation

Background: Studies of prenatal cocaine exposure have primarily examined childhood populations. Studying adolescents is especially important because adolescence is a time of changing motivations and initiation of substance use.

Methods: Using magnetic resonance imaging and whole-brain voxel-based morphometry, we assessed gray matter volume (GMV) differences in 42 prenatally cocaine exposed (PCE) and 21 noncocaine-exposed (NCE) adolescents, aged 14 to 17 years. Associations between GMV differences in significant clusters and the probability of substance use initiation were examined.

Results: PCE relative to NCE adolescents demonstrated three clusters of lower GMV involving a limbic and paralimbic (p < .001, family-wise error [FWE] corrected), superior frontal gyrus (p = .001, FWE corrected), and precuneus (p = .019, FWE corrected) cluster. GMVs in the superior frontal and precuneus clusters were associated with initiation of substance use. Each 1-mL decrease in GMV increased the probability of initiating substance use by 69.6% (p = .01) in the superior frontal cluster and 83.6% (p = .02) in the precuneus cluster.

Conclusions: PCE is associated with structural differences in cortical and limbic regions. Lower GMVs in frontal cortical and posterior regions are associated with substance use initiation and may represent biological risk markers for substance use.