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.Abstract Teaser