Extremes in mood, thought and behavior--including psychosis--have been linked with artistic creativity for as long as man has observed and written about those who write, paint, sculpt or compose. The history of this long and fascinating association, as well as speculations about its reasons for being, have been discussed by several modern authors and investigators, including Koestler (1975), Storr (1976), Andreasen (1978), Becker (1978), Rothenberg (1979), Richards (1981), Jamison (in press) and Prentky (in press). The association between extreme states of emotion and mind and creativity not only is fascinating but also has significant theoretical, clinical, literary and societal-ethical implications. These issues, more thoroughly reviewed elsewhere (Jamison et al. 1980; Richards 1981; Jamison, in press), include the understanding of cognitive, perceptual, mood and behavioral changes common to manic, depressive and creative states; the potential ability to lessen the stigma of mental illness; effects of psychiatric treatment (for example, lithium) on creativity; and concerns raised about genetic research on mood disorders. The current study was designed to ascertain rates of treatment for affective illness in a sample of eminent British writers and artists; to study differences in subgroups (poets, novelists, playwrights, biographers, artists); to examine seasonal patterns of moods and productivity; and to inquire into the perceived role of very intense moods in the writers' and artists' work. One of the major purposes of this investigation was to look at possible similarities and dissimilarities between periods of intense creative activity and hypomania. Hypothesized similarities were based on the overlapping nature of mood, cognitive and behavioral changes associated with both; the episodic nature of both; and possible links between the durational, frequency and seasonal patterns of both experiences.