Adjunctive High-Definition Transcranial Direct Current Stimulation in Brain Glutamate-Glutamine and γ-Aminobutyric Acid, Withdrawal and Craving During Early Abstinence Among Patients With Opioid Use Disorder on Buprenorphine-Naloxone: A Proton Magnetic Resonance Spectroscopy-Based Pilot Study.

OBJECTIVE: Our study aimed to (1) examine the effect of adjunctive high-definition transcranial direct current stimulation (HD-tDCS) in craving and withdrawal among patients with opioid use disorder on buprenorphine-naloxone, and (2) examine effect of HD-tDCS changes in glutamate-glutamine and γ-aminobutyric acid (GABA) at the left dorsolateral prefrontal cortex (DLPFC) among patients with opioid use disorder on buprenorphine-naloxone. METHODS: This was a pilot randomized double-blind, sham-controlled parallel-group study. A total of 28 patients on buprenorphine-naloxone (6/1.5 mg/d) were randomly allocated into 2 groups for active and sham HD-tDCS stimulation. High-definition transcranial direct current stimulation was administered twice daily for consecutive 5 days, from days 2 to 6. The Clinical Opiate Withdrawal Scale (COWS), the Desire for Drug Questionnaire (DDQ), the Obsessive-Compulsive Drug Use Scale (OCDUS), and glutamate-glutamine and GABA at DLPFC via proton magnetic resonance spectroscopy were measured at baseline and on day 7. RESULTS: Both active and sham groups had comparable changes in DDQ, OCDUS (except 2 subcomponents), COWS, and glutamate-glutamine and GABA at DLPFC. In the active HD-tDCS group, statistically significant reductions were observed in DDQ, OCDUS, and COWS but not in glutamate-glutamine and GABA. CONCLUSIONS: The adjunctive active HD-tDCS group showed comparable changes in craving and withdrawal, and glutamate-glutamine and GABA at DLPFC compared with sham HD-tDCS. Craving and withdrawal but not glutamate-glutamine and GABA at DLPFC decreased significantly with adjunctive HD-tDCS. Future studies with larger sample size and online assessment of glutamate-glutamine and GABA would enhance our knowledge.

Adjuvant High-Definition Transcranial Direct Current Stimulation for Negative Symptoms in Schizophrenia: A Pilot Study.

OBJECTIVE: In schizophrenia, negative symptoms account for a substantial amount of the comorbidity resulting in poor performance in social interaction, interpersonal relationships, economic functioning, and recreational activities. Research has implicated hypofrontality in the pathogenesis of negative symptoms of schizophrenia. Conventional transcranial direct current stimulation (tDCS) to the dorsolateral prefrontal cortex has attracted significant interest as an add-on treatment for negative symptoms in schizophrenia. High-definition tDCS (HD-tDCS), an optimized form of tDCS, has the potential for more focalized neuromodulation. Hence, we aimed to evaluate the efficacy of HD-tDCS over the left dorsolateral prefrontal cortex in the improvement of negative symptoms in schizophrenia. METHODS: Fourteen patients with schizophrenia with predominantly negative symptoms were enrolled for this pilot, randomized, sham-controlled, double-blind trial. Each participant received 10 sessions of HD-tDCS at 2 mA for 20 minutes twice daily over 5 days. Negative symptoms were assessed with the Scale for Assessment of Negative Symptoms and Positive and Negative Syndrome Scale for Schizophrenia. The Calgary Depression Scale for Schizophrenia was used to rule out depressive symptoms. Assessments were carried out at baseline and at 2 weeks. RESULTS: The improvement in negative symptoms in the active group was statistically significant at P value of 0.05 as compared with the sham group. CONCLUSION: These results suggest that HD-tDCS may lead to improvement in negative symptoms of schizophrenia. Its use as an adjunct to pharmacological treatment of negative symptoms may be worth considering.