It’s obviously too soon to know how the Affordable Care Act will effect health care in the United States. However, researchers from the University of California, Davis and the University of Rochester have completed a study to see how having any type of health insurance affects individuals. In particular, the scientists were interested in whether people adopt riskier behavior and/or use more health services after acquiring insurance, one of the fears of people opposed to universal coverage.
Jerant A, Fiscella K, Tancredi DJ, & Franks P (2013). Health insurance is associated with preventive care but not personal health behaviors. Journal of the American Board of Family Medicine : JABFM, 26 (6), 759-67 PMID: 24204073.