Effect of des-tyrosine-gamma-endorphin in tardive dyskinesia

The endorphin neuropeptides may have neuroleptic-like effects on dopamine function and may be antischizophrenic. Ten chronic psychotic patients with neuroleptic-induced tardive dyskinesia and parkinsonism received placebo and des-tyrosine-gamma-endorphin (DT gamma E). Drug effects on movement disorders and eye-blinking rates were assessed by blind evaluations of randomly sequenced videotapes made during standardized examinations before and 30, 60, and 120 minutes after each injection and at 24 hours postinjection on days of consecutive treatment. Changes in schizophrenic symptoms were evaluated openly with the schizophrenia subscale of the Comprehensive Psychiatric Rating Scale. There were no significant effects of DT gamma E on any parameter and no side effects. This suggests that DT gamma E, within the tested dose range, does not influence the pathophysiology of neuroleptic-induced dyskinesias or chronic schizophrenia or have neuroleptic properties. However, DT gamma E is well tolerated and should be tested with higher doses during prolonged treatment.