Methamphetamine users show greater than normal age‐related cortical gray matter loss

ABSTRACT Background Methamphetamine (Meth) abuse continues to be a major illicit drug of abuse. Neuroimaging findings suggest that Meth is neurotoxic and may alter various brain structures, but the effect of Meth on the aging brain has not been studied. Aim The aim was to determine regional volumes of cortical gray matter in the brains of adult Meth users versus healthy control subjects, and their interaction with age and Meth‐usage variables. Design Cross‐sectional study Setting Magnetic resonance imaging (MRI) Research Center located in a university‐affiliated hospital. Participants Thirty‐four Meth‐dependent subjects (21 men and 13 women; ages 33.1 ± 8.9 years), diagnosed according to DSM‐IV criteria, and 31 healthy non‐Meth user comparison subjects (23 men and 8 women ages 35.7 ± 8.4 years). Measurement Regional gray matter volumes were segmented automatically in all subjects and evaluated in relation to age, using high‐resolution MRIs at 3.0 Tesla. Findings After adjustment for the effects of cranium size, the Meth users showed enhanced cortical gray matter volume loss with age in the frontal (analysis of covariance interaction P = 0.02), occipital (interaction P = 0.01), temporal (interaction P < 0.001) and the insular lobes (interaction P = 0.01) compared to controls, independently of Meth‐usage patterns. Additionally, Meth users showed smaller gray matter volumes than control subjects in several subregions (dorsolateral prefrontal: P = 0.02; orbitofrontal: P = 0.03; prefrontal: P = 0.047; superior temporal: P = 0.04). Conclusions Methamphetamine users appear to show increased cortical gray matter loss with age which raises the possibility of accelerated decline in mental functioning.