Psychologkal Bulletin Copyright 1985 by the American Psychological Association, Inc. 1985, Vol. 98. No. 2, 31 0033-2909/85/$00.75 Stress, Social Support, and the Buffering Hypothesis Sheldon Cohen Thomas Ashby Wills Carnegie-Mellon University Cornell University Medical College The purpose of this article is to determine whether the positive association between social support and well-being is attributable more to an overall beneficial effect of support (main- or direct-effect model) or to a process of support protecting persons from potentially adverse effects of stressful events (buffering model). The review of studies is organized according to (a) whether a measure assesses support structure or function, and (b) the degree of specificity (vs. globality) of the scale. By structure we mean simply the existence of relationships, and by function we mean the extent to which one's interpersonal relationships provide particular resources. Special at- tention is paid to methodological characteristics that are requisite for a fair com- parison of the models. The review concludes that there is evidence consistent with both models. Evidence for a buffering model is found when the social support measure assesses the perceived availability of interpersonal resources that are re- sponsive to the needs elicited by stressful events. Evidence for a main effect model is found when the support measure assesses a person's degree of integration in a large social network. Both conceptualizations of social support are correct in some respects, but each represents a different process through which social support may affect well-being. Implications of these conclusions for theories of social support processes and for the design of preventive interventions are discussed. During recent years interest in the role of experiments, and prospective surveys suggest social support in health maintenance and dis- that social support is a causal contributor to ease etiology has increased (e.g., G. Caplan, well-being (cf. S. Cohen & Syme, 1985b; 1974; Cassel, 1976; Cobb, 1976; Dean & Lin, House, 1981; Kessler & McLeod, 1985; 1977; Gottlieb, 1981, 1983; Kaplan, Cassel, & Turner, 1983; Wallston, Alagna, DeVellis, & Gore, 1977; Sarason & Sarason, 1985). Nu- DeVellis, 1983). merous studies indicate that people with The purpose of this article is to consider the spouses, friends, and family members who process through which social support has a provide psychological and material resources beneficial effect on well-being. Although nu- are in better health than those with fewer sup- merous studies have provided evidence of a portive social contacts (Broadhead et al., 1983; relation (i.e., a positive correlation between Leavy, 1983; Mitchell, Billings, & Moos, 1982). support and well-being), in theory this result Although the many correlational results do not could occur through two very different pro- by themselves allow causal interpretation, cesses. One model proposes that support is re- these data in combination with results from lated to well-being only (or primarily) for per- animal research, social-psychological analogue sons under stress. This is termed the buffering model because it posits that support "buffers" (protects) persons from the potentially patho- Authorship of this article was equal. Order of authors genic influence of stressful events. The alter- was determined alphabetically. Preparation of this article native model proposes that social resources was partially supported by National Science Foundation have a beneficial effect irrespective of whether Grant BNS7923453, National Heart, Lung and Blood In- stitute Grant HL29547, and National Cancer Institute persons are under stress. Because the evidence Grant CA38243 to the first author and National Heart, for this model derives from the demonstration Lung and Blood Institute Grant HL/HD21891 and Na- of a statistical main effect of support with no tional Cancer Institute Grants CA25521 and CA33917 to Stress X Support interaction, this is termed the second author. Requests for reprints should be sent to Sheldon Cohen, the main-effect model. Understanding the rel- Department of Psychology, Carnegie-Mellon University, ative merits of these models has practical as Pittsburgh, Pennsylvania 15213. well as theoretical importance because each 310 SOCIAL SUPPORT AND THE BUFFERING HYPOTHESIS 311 has direct implications for the design of inter- standpoint of health psychology, several pro- ventions. spective epidemiological studies have shown This article reviews evidence relevant to a that social support is related to mortality. This comparative test of the main effect and buff- was shown in 9- to 12-year prospective studies ering models. We consider in detail the meth- of community samples by Berkman and Syme ods used to measure social support and the (1979) and House, Robbins, and Metzner methodological issues relevant to providing a (1982) and in a 30-month follow-up of an aged fair comparison of these models. Because sample by Blazer (1982). In these studies, much of the pioneering research in this area mortality from all causes was greater among was not theoretically designed, considerable persons with relatively low levels of social sup- diversity across different investigators exists in port. Similarly, several prospective studies us- the conceptualization and measurement of so- ing mental health outcome measures have cial support. Hence, results have disagreed, and shown a positive relation between social sup- previous discussions of the social support lit- port and mental health (Aneshensel & Frer- erature arrived at different conclusions about ichs, 1982; Billings & Moos, 1982; Henderson, whether social support operates through a Byrne, & Duncan-Jones, 1981; Holahan & buffering or main effect process (e.g., Mitchell, Moos, 1981; Turner, 1981; Williams, Ware, & Billings, & Moos, 1982;Broadheadetal., 1983; Donald, 1981). Gottlieb, 1981; Leavy, 1983). We posit that, The mechanisms through which social sup- in addition to conceptual inconsistencies, dif- port is related to mental health outcomes and fering results are often attributable to aspects to serious physical illness outcomes, however, of methodology and statistical technique. remain to be clarified. At a general level, it can Hence, we examine those characteristics of be posited that a lack of positive social rela- method and analysis that are relevant to an tionships leads to negative psychological states adequate test of the alternate models of the such as anxiety or depression. In turn, these support process. Detailed consideration is psychological states may ultimately influence given to issues that are particularly important physical health either through a direct effect for tests of interaction effects which have not on physiological processes that influence sus- been extensively discussed in previous sum- ceptibility to disease or through behavioral maries. patterns that increase risk for disease and We begin by presenting conceptual models mortality. In the following section, we outline of stress and support and discussing method- how social support could be linked to health ological and statistical issues that are crucial outcomes on a main effect basis and the mech- for comparing the main effect and buffering anism through which stress-buffering effects models. We then review literature published could occur. This framework is then used for through 1983, classifying studies according to reviewing literature on stress and support. the type of support measure used. The review is limited to studies of informal support sys- Support as a Main Effect tems such as family, friends, or co-workers and excludes studies of professional helpers (see, A generalized beneficial effect of social sup- e.g., DePaulo, Nadler, & Fisher, 1983; Nadler, port could occur because large social networks Fisher, & DePaulo, 1984). Because most of the provide persons with regular positive experi- studies reviewed in this article index symptoms ences and a set of stable, socially rewarded roles of psychological or physical distress rather than in the community. This kind of support could extreme disorder such as clinical depression be related to overall well-being because it pro- or chronic physical illness, we use the term vides positive affect, a sense of predictability symptomatology to refer to criterion variables. and stability in one's life situation, and a rec- ognition of self-worth. Integration in a social Models of the Support Process network may also help one to avoid negative experiences (e.g., economic or legal problems) Numerous studies have shown that social that otherwise would increase the probability support is linked to psychological and physical of psychological or physical disorder. This view health outcomes. Most important from the of support has been conceptualized from a so- 312 SHELDON COHEN AND THOMAS ASHBY WILLS ciological perspective as "regularized social that the potential for serious disorder occurs interaction" or "embeddedness" in social roles (cf. Wills & Langner, 1980). Mechanisms link- (Cassel, 1976; Hammer, 1981; Thoits, 1983, ing stress to illness include serious disruptions 1985) and from a psychological perspective of neuroendocrine or immune system func- as social interaction, social integration, rela- tioning, marked changes in health-related be- tional reward, or status support (e.g., Levinger haviors (e.g., excessive alcohol use, poor diet & Huesmann, 1980; Moos & Mitchell, 1982; or exercise patterns), or various failures