The author believes that adulthood as a developmental period has been conceptually and empirically ignored in the psychiatric literature with but few exceptions. Two studies on the subject are reported: an observational study of psychiatric outpatients seen in age-homogeneous groups and a questionnaire study of 524 nonpatients. The author found discriminations between age groupings that center largely on the subjects' sense of time and on their attitudes toward self and others in relation to that variable.Abstract Teaser