Acute versus chronic pain treatment in Alzheimer's disease.

Several studies have suggested a lower consumption of analgesics in patients with Alzheimer's disease (AD) than in cognitively intact individuals (ND), but little attention has been paid to a distinction in analgesic consumption between acute and chronic pain treatment. The aim of this prospective and longitudinal study is a comparison in AD and ND residents at selection, and one year later, of analgesic consumption for acute and chronic pain, with an assessment of cognitive status (with the Mini Mental State Examination (MMSE)). Three hundred institution residents (150 AD and 150 ND), 20% male and 80% female (84.4 +/- 8.3 years old), were included in this study. Analgesic consumption and MMSE were reassessed at one year's distance (period 1 P1 and 2 (P2)). Analgesic consumption for acute pain was not significantly different for AD and ND at selection time or one year later, while MMSE declined significantly for AD (6 +/- 7 (P1) versus 4 +/- 6 (P2) p < 0.01, and ND individuals 23 +/- 5 (P1) versus 20 +/- 6 (P2), p < 0.01, respectively). Chronic pain analgesic consumption however was significantly lower in AD than in ND (p < 0.01). These findings may suggest a dissociation between sensory-discriminative (lateral pain system) and motivational-affective (medial pain system) aspects of pain in individuals with AD. This dissociation must be further investigated as it may have important consequences for pain evaluation and pain treatment in this vulnerable population.