Three hypotheses derived from Hilde Bruch's formulations regarding onset differences among the obese were tested. In Bruch's theory, adult-onset, or reactive, obesity is a result of psychological trauma; the individual uses eating as a defense against anxiety and depression. Child-onset, or developmental, obesity results from a mixture of constitutional tendencies and severe emotional disturbances caused by faulty mother-child interactions; the individual uses indiscriminate feeding as a response to many distress states. It was hypothesized that: (1) adult-onset obese persons more often report weight gain due to significant life events; (2) child-onset obese persons are more depressed and anxious than adult-onset obese persons; and (3) child-onset obese persons have a more external locus of control. None of the hypotheses was supported, although the sample was quite different from the psychiatric patients observed by Bruch. An additional hypothesis derived from Bruch's observations regarding birth order--that child-onset obesity occurs more frequently among only or youngest child--did receive support. The findings also supported differentiations between adolescent-onset and child-onset obesity. (Author/CS)