Tested 129 patients, student nurses, and hospital employees with a 5-factor attitude scale, Opinions about Mental Illness, prior to and following psychiatric hospital experience. The group showed significant decreases in attitudes of authoritarianism and social restrictiveness toward mental patients. Attitude changes were not related to differences in indoctrination or time spent in the hospital. All significant attitude changes in the experimental group were in the direction of greater conformity to the attitudes of professional treatment staff or greater favorableness. A control group (N = 103) showed a significant decrease in belief in interpersonal etiology, but otherwise showed no significant changes. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.