Within the framework of longitudinal (cohort) research, in which children are followed into adulthood, we compared the results of a `child' questionnaire adjusted for age (Young Adult Self Report) with two existing `adult' ones (General Health Questionnaire, Symptom Checklist), for detecting psychopahology in young adults. The quality of the Young Adult Self Report as a screening instrument was found to be at least as well as the Symptom Checklist. Differences in performance between the General Health Questionnaire and both other self-assessment instruments were almost completely accounted for by lower values in sensitivity. An age adjusted `child' instrument appears a good alternative compared to an existing `adult' instrument, for the assessment of psychopathology in the young adult group.