Although previous studies support familial and individual relationships between creativity and affective illness, most have examined eminent creative individuals. This is the first study of creativity in subjects defined only by psychodiagnostic criteria. Creative accomplishment over the adult lifetime was assessed broadly using a new instrument, The Lifetime Creativity Scales, developed and validated for this research. Subjects were persons involved in a Danish adoption study. There were 44 index subjects (17 manic-depressives, 16 cyclothymes, 11 normal first-degree relatives) and 33 controls without a personal or family history of major affective disorder or cyclothymia (15 normal, 18 carrying another diagnosis). Orthogonal contrasts showed that normal and ill controls did not differ significantly from each other on creativity, but that creativity was higher in all index than control subjects and higher in normal relatives than in manic-depressives. Vocational and avocational creativity were also considered separately. Findings suggest that enhanced creativity may represent a compensatory advantage among individuals at risk for manic-depressive illness. (Author/NB)