Serum pseudocholinesterase in psychiatric patients.

Serum pseudocholinesterase activity was measured in 123 subjects: 16 agitated depressives, 12 retarded depressives, 7 acute schizophrenics, 14 residual schizophrenics, 16 healthy individuals, 45 surgical patients, and 13 first-degree relatives of 4 agitated depressive patients. The agitated depressive and acute schizophrenic patients had significantly higher pseudocholinesterase serum activity than their retarded inmates. As first-degree relatives of agitated depressive patients showed high levels similar to their ill relatives, a genetic component might play a crucial role. The level of pseudocholinesterase activity in serum of the surgical patients was significantly lower than that of all the psychiatric patients and the controls. The implications of this observation are still obscure.