Several decades of research attempting to explain schizophrenia regarding dopamine hyperactivity hypothesis have produced disappointing results. New hypotheses focusing on serotonin-dopamine interactions and hypofunction of the NMDA glutamate transmitter system have been emerging as potentially more promising concepts. The next generation of treatments for schizophrenia, whether they are based on dopamine, serotonin, or glutamate etc., should be effective on negative symptoms and cognitive deficits as well as positive symptoms. In this article, I review the brief overview of these hypotheses and new drugs based on the hypotheses.ope
