Seventeen trials were included in a Cochrane review . All trials examined the cognitive effects of selegiline, and in addition, 12 trials examined the behavioural and mood effects. There were very few significant treatment effects and these were all in favour of selegiline; cognition at 4-6 weeks and 8-17 weeks, and activities of daily living at 4-6 weeks. The meta-analysis revealed benefits on memory function, shown by improvement in the memory tests from several cognitive tests. The combined memory tests, and overall the combined cognitive tests, analysed using standardised mean differences, showed an improvement due to selegiline compared with placebo at 4-6 weeks and 8-17 weeks. The meta-analyses of emotional state show no treatment effects. Several studies assessed activities of daily living using several different scales. The combined tests, analysed using the standardised mean difference, showed an improvement due to selegiline at 4-6 weeks. The global rating scales analysed using standardised mean differences showed no effect of selegiline. RCTs assessing outcomes beyond 4 months found no significant difference between selegiline and placebo.