Keeler E B, Manning W G, Wells K B
J Health Econ. 1988 Dec;7(4):369-92. doi: 10.1016/0167-6296(88)90021-5.
Observational studies of demand for mental health services showed much greater use by those with more generous insurance, but this difference may have been due to adverse selection, rather than in response to price. This paper avoids the adverse selection problem by using data from a randomized trial, the RAND Health Insurance Experiment (HIE). Participating families were randomly assigned to insurance plans that either provided free care or were a mixture of first dollar coinsurance and free care after a cap on out-of-pocket spending was reached. We estimate that separate effects of coinsurance and the cap on the demand for episodes of outpatient mental health services. We find that outpatient mental health use is more responsive to price than is outpatient medical use, but not as responsive as most observational studies have indicated. Those with no insurance coverage would spend about one-quarter as much on mental health care as they would with free care. Coinsurance reduces the number of episodes of treatment, but has only a small effect on the duration and intensity of use within episodes. Users appear to anticipate exceeding the cap, and spend at more than the free rate after they do so.
对心理健康服务需求的观察性研究表明，保险福利更优厚的人群使用心理健康服务的频率要高得多，但这种差异可能是由于逆向选择，而非对价格的反应。本文通过使用来自随机试验“兰德健康保险实验（HIE）”的数据，避免了逆向选择问题。参与实验的家庭被随机分配到不同的保险计划中，有些计划提供免费医疗服务，有些则是在自付费用达到上限后采用一定比例的共付保险与免费医疗服务相结合的方式。我们估计了共付保险和费用上限对门诊心理健康服务次数需求的单独影响。我们发现，门诊心理健康服务的使用对价格的反应比门诊医疗服务更敏感，但不如大多数观察性研究所表明的那样敏感。没有保险覆盖的人群在心理健康护理上的花费约为享受免费医疗服务人群的四分之一。共付保险减少了治疗次数，但对每次治疗的时长和强度影响较小。使用者似乎预期会超过费用上限，在超过上限后会以高于免费治疗的费率消费。
