Cognitive function was studied after single and multiple doses of indomethacin (I) and matched placebo (P) in 20 healthy elderly volunteers using a double-blind crossover design. 2. Arousal, attention, integration, coordination, memory and mood were investigated using a battery of psychomotor tests and the Hospital Anxiety and Depression Scale. Assessments were performed before and after the first and last doses of a 7 day course of medication. 3. Critical flicker fusion threshold fell by a mean of 1.96% on indomethacin compared with a 1.13% rise on placebo 5 h after the first dose (P = 0.029). A beneficial effect on choice reaction time latency (P = 0.012) was seen both after acute and continuing administration of indomethacin. Performance at the most discriminating level (level 3) of the paired word association test was significantly better following 8 days of treatment with indomethacin in the younger (55-65 year-old) age group (P = 0.001). 4. There was no significant difference in performance on the symbol-digit substitution test and the continuous attention task. No change was seen in hospital anxiety and depression scale scores. 5. These results suggest that performance on tests of sensorimotor coordination and short term memory may improve in healthy volunteers following indomethacin administration, whereas tests of attention and psychomotor speed remain unaffected. However, further controlled studies in rheumatic patients are needed to evaluate fully the psychomotor effects of indomethacin and other NSAIDs in clinical practice.
