GABAergic dysfunction in early adolescents with subclinical psychotic experiences

Poster B116, Tuesday, October 9, 11:30 am - 1:00 pm, Essex Ballroom

Naohiro Okada1, Shintaro Kawakami1, Susumu Morita1, Daisuke Koshiyama1, Kentaro Morita1, Shinsuke Koike1, Shuntaro Ando1,2, Atsushi Nishida2, Richard A.E. Edden3,4, Peter B. Barker3,4, Akira Sawa3, Kiyoto Kasai1; 1The University of Tokyo, 2Tokyo Metropolitan Institute of Medical Science, 3The Johns Hopkins University School of Medicine, 4Kennedy Krieger Institute

Schizophrenia and psychosis are characterized by the impairment of GABAergic function. Although results are mixed, some previous MR spectroscopy (MRS) studies have demonstrated decreased brain GABA levels in patients with schizophrenia as well as in ultra-high-risk individuals. The question remains, however, whether such impairment may underlie the vulnerability to develop psychosis or the epiphenomena caused by medication exposure or illness chronicity. Subclinical psychotic experiences (SPEs) are sometimes present in adolescents in the general population, and increase the risk to develop psychosis in young adulthood. Investigations into association between SPEs and GABA levels in the general adolescents would answer the question. Here, we measured GABA+ levels in the anterior cingulate cortex (ACC) in a subsample (aged 10.5–13.4 years) of a large-scale population-based cohort using MRS (MEGA-PRESS), because the ACC is a key region of executive cognitive control and emotional regulation, which are sometimes impaired in patients with psychosis. In addition, we explored the alterations in ACC GABA+ levels related to SPEs (N=215). The MEGA-PRESS data were analyzed by using the Gannet software. The results showed that adolescents with SPEs had significantly lower GABA+ levels in the ACC (p = 0.043). We suggest that GABAergic dysfunction already existing in early adolescence may be a neural basis of premorbid state for the development of psychosis.

Topic Area: Ultra High Risk / Prodromal Research

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