At dosages of up to 600 mg of pentylenetetrazol (Metrazol), 450 mg of papaverine, and 45 mg of niacin per day, over a three-month period, only very small clinical changes were observed in 60 long-term psychotic geriatric patients randomly assigned to the three treatments. If one assumes niacin to be an active placebo, one finds that pentylenetetrazol elicits significantly more clinical improvement than placebo. This effect was modest and was not shown on other measures. Papaverine increased hallucinations relative to placebo. pentylenetetrazol increased motor retardation relative to placebo and improved hostility relative to papaverine. None of the treatments showed any significant differential effect in reducing intellectual impairment. Measures used included the BPRS, the NOSIE, and two scales, the Mental Status and Activities of Daily Living scales developed by Stotsky for use in studies of geriatric patients.
Lu L, Stotsky BA, Cole JO. A Controlled Study of Drugs in Long-term Geriatric Psychiatric PatientsA Double-Blind Comparison of Pentylenetetrazol, Papaverine, and Niacin. Arch Gen Psychiatry. 1971;25(3):284-288. doi:10.1001/archpsyc.1971.01750150092014