Molecular Pathogenesis for Schizophrenia and Major Depression

In schizophrenia, dopaminergic hyperfunction in the limbic system and dopaminergic hypofunction in the frontal cortex are discussed to be the main neurotransmitter disturbances. Recent research provides further insight that glutamatergic hypofunction might be the cause for this dopaminergic dysfunction. In major depression, in contrast, glutamatergic hyperfunction seems to be closely related to the lack of serotonergic and noradrenergic neurotransmission and to the core symptoms of major depression. Therefore, glutamatergic dysfunction seems to be a common pathway in the neurobiology of schizophrenia and depression. The function of the glutamatergic system is closely related to the immune system and to the tryptophankynurenine metabolism, which both seem to play a key role in the pathophysiology of schizophrenia and major depression (Müller and Schwarz, 2006, 2007).