Effects of placebo, orphenadrine, and rising doses of chlorpromazine, on PAT performance in chronic schizophrenia. A two year longitudinal study.

An earlier study (Study 1: 14 months duration) showed that the PAT (an auditory attention task) is sensitive to changes of clinical state in chronic schizophrenia and is able to predict hospital discharge. The newly presented study (Study 2: 12 months duration) investigated the effects of increasing the dose of chlorpromazine (CPZ) stepwise (double-blind) to between 900 mg and 1800 mg per day, in 10 of the original 20 patients. Measurements were made fortnightly throughout both studies and the data were depicted continuously for each patient. Study 2 showed that a 300% increase of CPZ dose neither improved nor impaired PAT performance. Also, the addition of orphenadrine 300 mg per day had no significant effect on performance. Four types of relapse were detected. The first was induced by placebo substitution for CPZ and recovered when the drug was reinstated. The remaining types of relapse were all resistant to CPZ and comprised: a long-period pattern with a spontaneous reversal; unremitting deterioration; and a short-period pattern of labile relapse and recovery.