HTR3A and schizophrenia: In addition to the 5HT2 receptors, mirtazapine inhibits the postsynaptic serotonin 5HT3 receptors and presynaptic noradrenaline α2 receptors and indirectly stimulates postsynaptic serotonin 5HT1A receptors (de Boer, 1996), all of these believed to be involved in the pathophysiology of schizophrenia.