S-adenosylmethionine-dependent N-methyltransferase activity in autopsied brain parts of chronic schizophrenics and controls

The transmethylation hypothesis of schizophrenia proposes that the disease results from excessive accumulation of methylated derivatives of biogenic amines. To test the hypothesis that an abnormality in S- adenosylmethionine-dependent N-methyltransferase (SAM enzyme) might play a role in schizophrenia, the authors compared SAM enzyme activity of in vitro preparations of 6 brain regions obtained at autopsy from chronic schizophrenics and nonschizophrenic controls. An analysis of variance demonstrated statistically significant differences among brain regions but not between schizophrenics and controls.