Introduction

Social ties are thought to affect mental and physical health by influencing emotions, cognitions, and behavior (Cohen, 1988, 2004). In the case of mental health, the hypothesis is that aspects of social relationships regulate these three response systems by preventing the occurrence of the kinds of extreme response that are associated with dysfunction. This regulation occurs through communication of social expectations, of appropriate norms, of rewards and punishments, and through the provision of coping assistance (Caplan, 1974; Cassel, 1976; Thoits, 1986). In the case of physical health, the hypothesis is that social ties influence behaviors with implications for health such as diet, exercise, smoking, alcohol consumption, sleep, and adherence to medical regimens. Moreover, the failure to regulate emotional responses can trigger health-relevant changes in the responses of the neuroendocrine, immune, and cardiovascular systems (Cohen, 1988; Cohen et al., 1994; Uchino, 2006).

During times of stress, social ties can be thought to operate by these same mechanisms to promote resilience, or positive adaptation in the face of adversity (Cohen & Wills, 1985; Luthar, 2006). People undergoing the stress of being diagnosed with a serious chronic illness are vulnerable to both physical and psychological adversity. Patients with chronic disease must cope with the physical threats of worsening health, loss of physical function, and the potential of a reduced lifespan, as well as with psychological threats such as feelings of isolation, loss of self-esteem, and loss of social and occupational role function.