The present work explores the impact of helping others on the physical and psychosocial well-being of the provider. Lay people were trained to listen actively and to provide compassionate, unconditional positive regard to others with the same chronic disease. The recipients of the peer support intervention were participants of a psychosocial randomized trial, whereas the peer supporters were study personnel and were therefore not randomized. We describe a secondary analysis of a randomized trial to explore the impact of being a peer supporter on these lay people. Subjects were 132 people with multiple sclerosis, all of whom completed quality-of-life questionnaires 3 times over 2 years. A focus group was also implemented with the peer telephone supporters 3 years after completion of the randomized trial. Effect size was computed for each quality-of-life outcome, and the focus group discussion was content analyzed. We found that compared to supported patients, the peer telephone supporters: (1) reported more change in both positive and negative outcomes as compared to the supported patients and that the effect size of these changes tended to be larger (chi2 = 9.6, df = 4, p < 0.05) and (2) showed pronounced improvement on confidence, self-awareness, self-esteem, depression and role functioning. Content analysis revealed that the participants articulated a sense of dramatic change in their lives in terms of how they thought of themselves and in how they related to others. We conclude with a discussion of response shift, a mediator of adaptation to illness which involves shifting internal standards, values, and concept definitions of health and well-being. We suggest that a response shift may be induced by a therapeutic strategy involving the externalization and re-internalization of concern among physically ill patients.