Mutual altruism: evidence from Alzheimer patients and their spouse caregivers.

Purpose: Preferences of both Alzheimer patients and their spouse caregivers are related to a willingness-to-pay (WTP) measure which is used to test for the presence of mutual (rather than conventional unilateral) altruism.

Methodology: Contingent valuation experiments were conducted in 2000-2002, involving 126 Alzheimer patients and their caregiving spouses living in the Zurich metropolitan area (Switzerland). WTP values for three hypothetical treatments of the demented patient were elicited. The treatment Stabilization prevents the worsening of the disease, bringing dementia to a standstill. Cure restores patient health to its original level. In No burden, dementia takes its normal course while caregiver's burden is reduced to its level before the disease.

Findings: The three different types of therapies are reflected in different WTP values of both caregivers and patients, suggesting that moderate levels of Alzheimer's disease still permit clear expression of preference. According to the WTP values found, patients do not rank Cure higher than No burden, implying that their preferences are entirely altruistic. Caregiving spouses rank Cure before Burden, reflecting less than perfect altruism which accounts for some 40 percent of their total WTP. Still, this constitutes evidence of mutual altruism. VALUE: The evidence suggests that WTP values reflect individuals' preferences even in Alzheimer patients. The estimates suggest that an economically successful treatment should provide relief to caregivers, with its curative benefits being of secondary importance.