<prompt> The most commonly implicated neurotransmitter in the aetiology of schizophrenia isNorepinephrineSerotoninDopamineGABA  <response>: Schizophrenia is presently thought to be probably due to a functional increase of dopamine at the postsynaptic receptor, though other neurotransmitters such as serotonin especially 5-HT2 receptors, GABA and acetylcholine are also presumably involved. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 63 