Heightened excitability and impaired Inhibition in methamphetamine users: a pilot study of neurophysiological correlates of psychological symptoms
Year: 2026
Type: article
Study design: Observational Study
Abstract: BACKGROUND: In this study, we investigated transcranial magnetic stimulation (TMS)-derived markers of excitability and inhibition in methamphetamine (METH) use disorder. METHODS: Sixteen methamphetamine users and 20 matched controls underwent psychological assessments, revised form of Symptom Checklist-90-Revised, cognitive assessment, anxiety and depression scales and TMS measures, including resting and active motor thresholds (RMT and AMT), motor evoked potential amplitude (MEP-A), cortical silent period (CSP), and short-interval intracortical inhibition (SICI). RESULTS: METH users reported higher anxiety, depression, and somatization (p < 0.001), while cognition remained preserved. They exhibited reduced RMT and AMT (p < 0.001), indicating increased excitability, with no significant differences in MEP-A (p = 0.083). CSP onset latency was prolonged at 150% RMT (p = 0.042), suggesting impaired inhibition. Excitability thresholds correlated negatively with methamphetamine dose, while addiction duration was linked to CSP changes and obsessive-compulsive symptoms. Lower thresholds also correlated with greater interpersonal sensitivity and addiction severity. CONCLUSION: Increased cortical excitability and decreased inhibitory control are linked to METH usage, and these factors may be underlying psychiatric symptoms. TMS-derived indices show potential as biomarkers for neurophysiological monitoring and targeted interventions in methamphetamine use disorder.
Source: Psychopharmacology
Authors: Eman M. Khedr, Yasser Elserogy, Abdelrahman Goda, Mohamed Fawzy
Institution: Assiut University
Language: English
Subfield: Neurology
Field: Neuroscience
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $4,390
OpenAlex ID: W7124745748