The objective of this study was to compare adolescents' attitudes toward schizophrenia, depression, and posttraumatic stress disorder (PTSD). Stigmatizing attitudes toward these three mental disorders were evaluated in 325 senior students from medical, commercial, and grammar high schools in Croatia using a 45-item questionnaire. Results indicated that stigmatizing attitudes toward PTSD were at the same level as attitudes toward depression and were less stigmatizing than were attitudes toward schizophrenia. Negative attitudes were the lowest among medical students. Gender differences existed only for attitudes toward depression. Stigmatizing attitudes toward PTSD were not as high as expected. All of the students believed mental disorders are different from other disorders. Specific knowledge of psychiatry has been shown to reduce stigma. The nonaddictive nature of psychotropic medications should receive greater emphasis when teaching psychiatry.