Methamphetamine (METH) dependence is a globally significant public health concern with no efficacious treatment. Trait impulsivity is associated with the initiation, maintenance, and recurrence of substance abuse. However, the presence of these associations in METH addiction, as well as the underlying neurobiological mechanisms, remains incompletely understood.

We scanned 110 individuals with METH use disorder (MUDs) and 55 matched healthy controls (HCs) using T1-weighted imaging and assessed their drug use characteristics and trait impulsivity. Surface-based morphometry and graph theoretical analysis were used to investigate group differences in brain morphometry and network attributes. Partial correlations were conducted to investigate the relationships between brain morphometric changes, drug use parameters, and trait impulsivity. Mediation analyses examined how trait impulsivity and drug craving influenced the link between brain morphometric change and MUD severity in patients.

MUDs exhibited thinner thickness in the left fusiform gyrus and right pars opercularis, as well as diminished small-world properties in their structural covariance networks (SCNs) compared to HCs. Furthermore, reduced cortical thickness in the right pars opercularis was linked to motor impulsivity (MI) and MUD severity, and the association between the right pars opercularis thickness and MUD severity was significantly mediated by both MI and cue-induced craving.

These findings suggest that MUDs exhibit distinct brain structural abnormalities in both the cortical thickness and SCNs and highlight the critical role of impulse control in METH addiction. This insight may offer a potential neurobiological target for developing therapeutic interventions to treat addiction and prevent relapse.

Repetitive transcranial magnetic stimulation has been employed to treat drug dependence, reduce drug use and improve cognition. The aim of the study was to analyze the effectiveness of intermittent theta-burst stimulation (iTBS) on cognition in individuals with methamphetamine use disorder (MUD).

This was a secondary analysis of 40 MUD subjects receiving left dorsolateral prefrontal cortex (L-DLPFC) iTBS or sham iTBS for 20 times over 10 days (twice-daily). Changes in working memory (WM) accuracy, reaction time, and sensitivity index were analyzed before and after active and sham rTMS treatment. Resting-state EEG was also acquired to identify potential biological changes that may relate to any cognitive improvement.

The results showed that iTBS increased WM accuracy and discrimination ability, and improved reaction time relative to sham iTBS. iTBS also reduced resting-state delta power over the left prefrontal region. This reduction in resting-state delta power correlated with the changes in WM.

Prefrontal iTBS may enhance WM performance in MUD subjects. iTBS induced resting EEG changes raising the possibility that such findings may represent a biological target of iTBS treatment response.