['Psychiatric patients, as well as humans or experimental animals with brain lesions, often concurrently manifest behavioral deviations and subtle cognitive impairments. This study tested the hypothesis that as a group, adolescents suffering from psychiatric disorders score worse on cognitive tests compared with controls.', 'As part of the assessment for eligibility to serve in the military, the entire, unselected population of 16-17-year old male Israelis undergo cognitive testing and screening for psychopathology by the Draft Board. We retrieved the cognitive test scores of 19 075 adolescents who were assigned any psychiatric diagnosis, and compared them with the scores of 243 507 adolescents without psychiatric diagnoses.', 'Mean test scores of cases were significantly poorer then controls for all diagnostic groups, except for eating disorders. Effect sizes ranged from 0.3 to 1.6.'] Is cognitive performance of male adolescents lower than controls across psychiatric disorders : a population-based study?