How does methamphetamine affect the brain? A systematic review of magnetic resonance imaging studies

Methamphetamine (METH) is an addictive psychostimulant that is associated with significant physical and psychological harm. Magnetic resonance imaging (MRI) is a non-invasive imaging modality used to identify structural and functional brain changes. We conducted a systematic review to identify and appraise the existing literature on brain MRI differences associated with METH exposure. A comprehensive literature search was conducted on PubMed, Web of Science, and Scopus. Any study that evaluated the brain in people who used or had been exposed to METH using MRI were included. Data were collected on study design, participant demographics, METH use parameters, MRI acquisition details, and key findings. One hundred and eighty-one studies with 11997 participants were included in our review. Nearly all were conducted in adults/adolescents (164/181, 91 %), and most studies were cross-sectional (142/181, 78 %). Task-based functional MRI was the most common modality used (62/181, 34 %), followed by structural MRI (47/181, 26 %). Quality appraisal scores ranged from 40 - 100 % (mean 90 %). Overall, METH is associated with numerous differences in brain structure and function, including lower grey matter volume and thickness in frontal and limbic regions and lower fractional anisotropy in various white matter structures, with differences in socio-emotional functioning, decision-making and learning processes, and cognitive performance. Targeted multi-modal MRI sequences may be useful in further clarifying the brain differences associated with METH use and evaluating the use of potential therapeutic agents.