Initial studies at the Centre for Addiction and Mental Health here show at least two antipsychotics should be prescribed at lower doses than what is standard practice. In one study of 22 patients with schizophrenia, subjects responded to much lower doses of the antipsychotic haloperidol than what is normally prescribed, and avoided major side-effects. Once on higher doses, a tolerance is developed. If doctors wish to get patients on lower doses, a dose reduction needs to be done gradually, perhaps over a period of months, he said.
Antipsychotics work by blocking the transmission of dopamine.
Unfortunately, using PET scans to reduce side-effects probably won't work with every drug or every disease. The study also showed there is some variation in individual response to haloperidol. This is preferable to starting with a higher dose and risking side-effects from the start. Findings from the study of haloperidol are published in the April issue of the American Journal of Psychiatry. The scans can be used to do the original dosing studies before drugs are approved, or to confirm whether or not recommended doses are at the best levels.