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The following is a summary of “Excitation/inhibition imbalance in schizophrenia: a meta-analysis of inhibitory and excitatory TMS-EMG paradigms,” published in the June 2024 issue of Psychiatry by Lányi et al.

Cortical excitation-inhibition (E/I) imbalance is seen as a critical model for understanding schizophrenia. Prior studies using transcranial magnetic stimulation (TMS) and electromyography (EMG) have indicated inhibitory deficits in this condition.

Researchers conducted a retrospective study evaluating TMS-EMG paradigms’ reliability and clinical relevance in schizophrenia, following PRISMA and Cochrane guidelines. 

They searched 3 databases in November 2022 for studies on Short-Interval Intracortical Inhibition (SICI), Intracortical Facilitation (ICF), Long-Interval Intracortical Inhibition (LICI), and Cortical Silent Period (CSP) in schizophrenia and HCs. Meta-analyses using random-effects models were performed, with subgroup analyses and meta-regressions assessing heterogeneity.

The results showed that analysis of 36 studies revealed a consistent inhibitory deficit in schizophrenia, notably with a significant decrease in SICI (Cohen’s disease: 0.62). A suggestive link between SICI and antipsychotic medication use was observed. 

Investigators concluded that E/I imbalance correlated with schizophrenia and reduced SICI may be a key pathophysiological feature of the disorder. 

Source: nature.com/articles/s41537-024-00476-y