Disruption of glutamate-glutamine-GABA cycle significantly impacts on suicidal behaviour: survey of the literature and own findings on glutamine synthetase - Bernstein, H-G; Tausch, A; Wagner, R; Steiner, J; Seeleke, P; Walter, M; Dobrowolny, H; Bogerts, B (CNS & Neurological Disorders – Drug Targets, 2013)