Work

Distinct cortical inhibitory profiles in schizophrenia and bipolar disorder: A TMS-EEG study of GABAb function

Year: 2025

Type: article

Abstract: EEG recordings associated with transcranial magnetic stimulation (TMS) with paired pulse paradigms allow the in vivo assessment of cortical inhibitory function. The long-interval cortical inhibition (LICI) paradigm can be used to estimate this function related to GABAb receptors. We compared LICI values between 25 patients with schizophrenia, 16 patients with bipolar disorder (BD), and 23 healthy controls (HC). We also assessed the relationship between LICI values and cognitive performance, as well as the treatment with antipsychotics, benzodiazepines, and anticonvulsants. LICI was significantly lower in patients with schizophrenia than in controls, but not in BD patients. In the former group, LICI was negatively associated with cognitive performance and positive symptoms. However, benzodiazepines increased LICI values, which does not explain its decrease in schizophrenia patients. Our data support the existence of a functional inhibitory deficit mediated by GABAb receptors in schizophrenia, that is associated with cognitive performance and symptoms. In the context of existing literature, this deficit may characterize a subgroup of patients with this diagnosis. • Using transcranial magnetic stimulation and paired pulses to assess long-interval cortical inhibition (LICI), likely related to GABA-b receptors function in schizophrenia and bipolar patients and healthy controls. • We found a significant deficit of LICI in schizophrenia but not in bipolar patients as compared to healthy controls. • In schizophrenia patients, LICI was correlated with cognitive performance. • Treatment, including benzodiacepines and anticonvulsant drugs, dis not explain LICI results.

Source: Progress in Neuro-Psychopharmacology and Biological Psychiatry

DOI: 10.1016/j.pnpbp.2025.111593