MR spectroscopy glutamate measures reflect craving for heroin in addicts

New MR spectroscopy findings indicate that changes in brain glutamate levels reflect changes in heroin craving among addicts during methadone maintenance therapy. MRS may eventually help predict whether addicts will relapse after treatment.

Animal studies have previously shown that glutamate is involved in the development and expression of drug addiction. Drug exposure and withdrawal change the glutamate levels in the anterior cingulate cortex, ventral striatum, thalamus, and hippocampus.

Dr. Mark Greenwald and colleagues at Wayne State University established for the first time that glutamate changes can be measured in humans. Their data demonstrate a significant correlation between glutamate levels and heroin craving during methadone detoxification therapy.

Six heroin addicts aged 31 to 55 years and healthy age-matched controls participated in the study.

Baseline H-1 MR spectroscopic scans were completed several days after the start ofa methadone treatment regimen. Follow-up MRS evaluations were performed about one month after the baseline scan.All patients showed significantly lower glutamate levels in the anterior cingulate while they received the high methadone dosage than during lower dose administrations (p