BCHE and schizophrenia: This is particularly compelling considering that the S-(−)-isomer, which possesses 60 times greater β-blocking activity than the R-(+)-isomer (Howe and Shanks, 1966), is less effective in reducing symptoms of manic psychosis and schizophrenia (Gruzelier et al., 1979), suggesting that mechanisms beyond β-blockade—such as cholinesterase inhibition—may play a significant role (Whittaker et al., 1982).