Excretion patterns of tryptamine, indoleacetic acid, and 5-hydroxyindoleacetic acid, and their correlation with mental changes in schizophrenic patients under medication with alpha-methyldopa.

Abstract

Ten chronic schizophrenic patients received α-methyldopa during 13 weeks, in doses up to 6 Gm/day. The patients were evaluated psychiatrically and, simultaneously, their urinary excretion of 5-hydroxyindoleacetic acid, tryptamine, and indoleacetic acid was determined. Two patients became psychotic, five others showed worsening of their condition, two patients remained unaffected, and one patient improved. Urinary 5-hydroxyindoleacetic acid was uniformly decreased in all patients. The amount of tryptamine excretion seemed to be correlated to the severity of the psychiatric changes. Urinary indoleacetic acid output generally followed the pattern of tryptamine excretion. These findings indicate that the blocking of serotonin synthesis by α-methyldopa is not accompanied by psychiatric improvement, and that high tryptamine levels, perhaps in combination with lowered serotonin tissue levels, appear to be a factor in the development of psychosis.