Background: Short-term studies of L-deprenyl in Alzheimer's disease (AD) suggest a beneficial effect, whereas longer-term studies are less convincing. Accordingly, we undertook a 6-month, randomized, double-blind, placebo-controlled clinical trial to assess the potential benefit of L-deprenyl in AD.
Methods: Sixty subjects were assigned to L-deprenyl (10 mg daily) or placebo. After 4 weeks of single-blind placebo, 51 subjects entered the double-blind phase. The Brief Psychiatric Rating Scale (BPRS) was the primary outcome measure. Secondary outcome measures were the Mini-Mental State Examination, Global Deterioration Scale, Alzheimer's Disease Assessment Scale (noncognitive), Cornell Scale for Depression in Dementia, Buschke Selective Reminding Test (BSRT), Relative's Assessment of Global Symptomatology-Elderly (RAGS-E), Controlled Oral Word Association Test, and Modified Continuous Performance Test. In addition, several exploratory tasks were included for future hypothesis testing.
Results: We found no significant differences between the L-deprenyl and placebo groups on the primary or secondary measures. However, several measures appeared to be sensitive to change over time, including the total score on the BPRS and some of its components as well as parts of the BSRT and the RAGS-E.
Conclusion: Oral L-deprenyl provides no detectable benefit on general behavior, neuropsychiatric symptoms, or cognitive function in AD after 6 months of treatment. Protocols for future drug studies should utilize measures that are sensitive to change over time such as the BPRS.