Frontocortical N-acetylaspartate reduction associated with long-term i.v. heroin use.

To examine possible metabolic frontal lobe alterations in i.v. heroin-dependent patients with different histories of concomitant substance use, N-acetylaspartate (NAA), a putative marker of neuronal viability, was measured by (1)H-MRS. Compared with controls, NAA levels in patients were reduced by 7% in gray matter (p = 0.015) but not in white matter. To what extent comorbid conditions or substance use, including alcohol, contributed to these frontocortical metabolic changes remains to be elucidated.