9 Personality Traits as Risk Factors for Physical llness The belief that stable patterns of thought, emotion, and behavior contribute to the development of physical illness has been present throughout the history of medicine (McMahon, 1976) Hippocrates, for example, argued that four basic temperaments or personality types reflected excesses of specific humors and caused corresponding medical disorders Many centuries later, Sir William Osler (1892) suggested that coronary heart disease befell “not the neurotic, delicate person …but the robust, the vigorous in mind and body, the keen and ambitious man, the indicator of whose engine is always at full speed ahead” (p 839) The descriptions of personality, disease, and the nature of their relation have varied widely, but the essence of this psychosomatic hypothesis has remained unchanged Earlier in this century, the hypothesis was refined by the psychoanalytic school in psychosomatic medicine (Alexander, 1950; Dunbar, 1943) These models assigned a pathophysiological role to unconscious personality dynamics, and suggested a correspondence between specific emotional conflicts and medical conditions Unlike previous psychoanalytic formulations of hysteria or hypochondriasis (Freud, 1933), these models identified causes for actual disease, rather than unfounded physical symptoms For example, an unconscious conflict between aggressive impulses and anxiety concerning the consequences of their expression was described as a cause of essential hypertension Although a weak scientific foundation limited the impact of this approach on the mainstream of either medicine or psychology (Surwit, R B Williams, & Shapiro, 1982), it set the stage for current research on personality and illness During the same period, developments in the physiology of stress provided an essential, scientifically credible set of mechanisms connecting personality and disease (Ax, 1953; Cannon, 1939; Seyle, 1936, 1952; Wolff, 1950) Not surprisingly, the psychophysiology of stress and emotion remains an integral component of this research area (Contrada, Leventhal, & O'Leary, 1990) The immediate predecessor of the current interest in the issue is undoubtedly the seminal work of M Friedman and Rosenman (1959) on the Type A coronary prone behavior pattern Although M Friedman and Rosenman actively avoided describing their work in the language of personality traits, their work is now recognized as involving personality characteristics (Suls & Rittenhouse, 1987) Friedman and Rosenman's version of the centuries- old psychosomatic hypothesis was a major force in the early development of the larger fields of behavioral medicine and health psychology (G C Stone, F Cohen, & Adler, 1979; Weiss, Herd, & Fox, 1981) An often overlooked forerunner to current research on personality traits as risk factors for illness are early studies that used psychometrically sound measures of personality in large, prospective designs (e.g., Ostfeld, Lebovits, Shekelle, & Paul, 1964) Effects of personality variables on subsequent disease were examined while attempting to control statistically the possible confounding medical or demographic variables Studies of this type provided important evidence of the merit of the hypothesis and the outlines of a methodology for constructing a credible epidemiological foundation for the field The current state of research on the hypothesis that personality traits can influence physical health comprises notable achievements and clear limitations On the one hand, several literatures have matured to the point that the evidence is compelling; specific personality characteristics are indeed associated with increased risk of serious illness and premature death (e.g., T Q Miller, T W Smith, Turner, Guijarro, & Hallet, 1996) Further, plausible mechanisms accounting for this association have been articulated and evaluated, at least in a preliminary manner (S Cohen & Herbert, 1996; Manuck, 1994) On the other hand, a steady climate of skepticism persists in much of the medical community (e.g., Angel, 1985), and the empirical support for the health relevance of some personality traits discussed in this literature is quite limited Further, the implications of this work for the treatment and prevention of illness are largely unknown Fortunately, conceptual, methodological, and analytic tools in personality psychology and behavioral medicine have evolved to the point where future studies will address these limitations in an increasingly compelling manner This chapter provides an overview and critique of the literature concerning personality traits as risk factors for physical disease It begins by addressing some basic issues regarding the nature of personality, disease, and their potential association After reviewing models of this association, it turns to theory and research on the major personality attributes in the field Finally, it concludes with a critical evaluation of the state of the literature and issues to be addressed in its future BASIC ISSUES What Is Personality? Allport (1937) succinctly argued that “personality is something and personality does something” (p 48, emphasis added) Personality traits are stable patterns of thought, emotion, and behavior that characterize an individual across time and situations Traits are presumed to be based in psychological and/or biological structures within the individual, and they form a dimensional basis for comparing individuals For example, some people are generally friendly and warm, whereas others are cold and disagreeable, presumably because of differences in their biologic and/or psychologic “make-up.” Thus, from this perspective, personality traits are things that people “have” (Cantor, 1990) In Allport's other, more active meaning, personality refers to the processes through which an individual's thoughts, emotions, and behavior cohere into meaningful patterns over time and across situations These processes include the ways in which individuals select and interpret the contexts and situations of their lives, the goals they pursue, the strategies and tactics they employ in doing so, and the ways in which they evaluate and react to the outcome of these activities These more circumscribed and dynamic psychological processes are closely associated with the stable patterns of thought, emotion, and behavior that are indicators of traits Yet, this other sense of personality is obviously much more concerned with how traits operate, rather than their description Thus, the study of personality as “doing” rather than having (Cantor, 1990) focuses on describing both the psychological mechanisms underpinning more broadly defined, static personality traits and the ways in which these “middle units” of personality are dynamically interrelated and expressed Current personality psychology reflects both of Allport's meanings, and recent developments of both types have the potential to make enormously valuable contributions to the study of personality and health (T W Smith & P G Williams, 1992) In the classic trait perspective, a far-reaching development is the emergence of the five-factor model of personality as an adequate taxonomy of basic personality characteristics (Digman, 1990; John, 1990; McCrae & John, 1992) Although descriptions vary across versions of this model, and despite several notable critics (e.g., Block, 1995), there is general consensus regarding the traits listed in Table 9.1- Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness to Experience These traits have been recovered in factor analyses of self- and other- ratings, and several reliable and valid measures of these broad dimensions and their subcomponents have been developed (Digman, 1990; John, 1990) The validity and potential impact of this taxonomy are evident in the fact that these traits are clearly not simple mental abstractions or linguistic conveniences used by raters (e.g., Funder & Colvin, 1991; Moskowitz, 1990) Rather, they reflect verifiable, general dimensions of individual functioning Further, these broadly defined traits are stable (McCrae & Costa, 1990), show patterns of variability consistent with genetic influences (Bouchard, Lylkken, McGue, Segal, & Tellegen, 1990), and predict behavior in many circumstances (Kendrick & Funder, 1988) The elements of this taxonomy can provide a useful guide for organizing the growing array of otherwise conceptually isolated traits suggested as risk factors for physical illness (Costa & McCrae, 1987b; Marshall, Wortman, Vickers, Kusulas, & Hervig, 1994; T W Smith & P G Williams, 1992) Traits studied as risk factors are often described and studied individually, without attention to their overlap or even redundancy with other traits One important application of the five-factor taxonomy is the conceptual and empirical description of traits suggested as potential risk factors This use of the five-factor taxonomy might reveal similarities and differences among otherwise isolated traits In addition, the five traits themselves might be viable candidates as risk factors (e.g., Costa, McCrae, & Dembroski, 1989) In either of these applications of the model, the well-validated assessment devices are likely to be useful to health researchers One important variation on the five-factor model substitutes the dimensions of Friendliness versus Hostility and Dominance versus Submissiveness for Agreeableness and Extraversion, respectively (Trapnell & Wiggins, 1990) This permits the integration of the five-factor approach with the interpersonal approach to personality (Carson, 1969; Kiesler, 1983; Leary, 1957; Wiggins, 1979) As depicted in Fig 9.1, the dimensions of dominance and friendliness define a two-dimensional space, or circumplex The circumplex model has been used, conceptually and empirically, to describe a variety of personality characteristics, interactional behaviors, and social stimuli (Kiesler, 1991; Wiggins, 1991; Wiggins & Broughton, 1991) As a result, it has considerable potential for facilitating the integration of personality and social risk factors for disease (Gallo & Smith, 1998; T W Smith, Gallo, Goble, Ngu, & Stark, 1998; T W Smith, Limon, Gallo, & Ngu, 1996) That is, personality traits and aspects of the social environment can be described and even assessed through a common framework Although the five-factor model and its variants are potentially invaluable in identifying and organizing traits in the study of personality and health, they have less to say about the mechanisms through which traits influence behavior, emotion, and ultimately health It is here that the second major emphasis in personality psychology is of use Unfortunately, less agreement exists regarding an adequate taxonomy of the “middle units” of personality processes (Cantor, 1990) However, several overlapping sets have been articulated, and clear themes have emerged in the related research These approaches follow from the cognitive social learning tradition in personality psychology (Kelly, 1955; Mischel, 1973; Rotter, 1954), and they share many conceptual similarities to interpersonal approaches in personality and clinical psychology (Kiesler, 1996; Westen, 1991) Examples of the constructs described in this literature are mental representations (i.e., schemas) of the self, others, relationships, and social interaction sequences (i.e., scripts); life tasks, motives, and goals; appraisals, values, and beliefs; strategies, tactics, and competencies in goal-directed behavior; and coping styles and behaviors (Cantor, 1990; McAdams, 1995; Mischel & Shoda, 1995, 1998; Oglevie & Rose, 1995; Westen, 1995) An underlying premise in this tradition is that characteristics of the person are reciprocally related to the social environment Intentionally or not, people choose to enter some situations and not others, and their actions and overt expressions of emotion elicit responses from their interaction partners in ways that reflect their personality traits (Asendorpf & Wilpers, 1998) These selected, evoked, and intentionally manipulated features of the individual's social environment in turn influence the individual (Bandura, 1977; Buss, 1987; Ickes, Snyder, & Garcia, 1997) Thus, an individual's thoughts, emotions, and behavior are seen as highly responsive to characteristics of the specific situation, and many situations are modified by the individual's actions Through these recurring, reciprocal patterns, individuals foster social environments that maintain central features of their personalities over time (Caspi et al., 1989; Kiesler, 1996; Wachtel, 1994; Wagner, Kiesler, & Schmidt, 1995) A further implication of this view is that personality processes are best understood in the contexts that comprise and surround these reciprocal interactions between people and social environments (Revenson, 1990), such as characteristics of the physical environment, subculture, and socioeconomic factors Personality descriptions are likely to be more accurate and informative to the extent that they consider individuals, their recurring social circumstances, and the context in which they are embedded Current versions of the cognitive-social approach to personality offer the potential for a comprehensive description of broad traitlike characteristics and recurring patterns of situationally specific responding (e.g., Mischel & Shoda, 1995, 1998) That is, the approach has the potential to describe the mechanisms through which traits, such as those in the five-factor taxonomy, influence thought, emotion, and behavior in interaction with social situations Another important advantage of the cognitive-social perspective is its overlap with current stress and coping theory, given their mutual emphasis on cognitive appraisal processes, self- regulation of emotional responses, and strategies for managing situational threats and demands (Contrada, 1994) The general stress and coping model (e.g., Lazarus & Folkman, 1984; Lazarus, 1991) has become a cornerstone of health psychology and behavioral medicine, and it provides an important conceptual and empirical connection to the psychophysiological responses hypothesized to link personality traits and subsequent disease Another benefit of the cognitive-social approach is its relevance for interventions Although the general trait approach is useful in identifying the personality characteristics that might be useful foci in interventions intended to prevent or manage illness, it has less to say about specific targets for change With its increased attention to specific psychological mechanisms and dynamic patterns, the cognitive-social approach is likely to aid in the articulation and refinement of intervention techniques For example, whereas the five-factor taxonomy might identify neuroticism and (low) agreeableness as useful targets for change, the cognitive-social perspective could suggest specific patterns of appraisals, beliefs, interaction tactics, and coping behaviors to be included in such interventions What Are the Appropriate Indications of Illness? A revolutionary difference between psychoanalytic writing on hysteria and hypochondriasis as opposed to the later work of Alexander, Dunbar, and their colleagues lies in the nature of the health endpoint under considerationabnormal illness behavior versus actual illness This distinction was clearly drawn more recently in conceptual discussions of the potential effects of personality on health (e.g., F Cohen, 1979) Outcomes such as symptom reports, utilization of health care resources (e.g., physician visits), taking medication, or receiving other treatments typically reflect the presence of illness, but are fallible indicators In evaluating the role of personality in physical illness, care must be taken to avoid mistaking an association between personality traits and illness behavior for an association with actual illness The former may or may not reflect the latter Despite the early and clear articulation of this issue, many influential empirical reports on the association between personality and physical illness relied heavily on these less definitive indices (e.g., Haynes, Feinleib, & Kannel, 1980; Kobasa, 1979; Scheier & Carver, 1985) Similarly, several important reviews of this literature (e.g., H S Friedman & Booth- Kewley, 1987) have been criticized for the potential misinterpretation of associations between personality traits and illness behaviors-especially somatic complaints-as reflecting the effects of personality on actual physical health (e.g., Matthews, 1988; Stone & Costa, 1990; T W Smith & Rhodewalt, 1991) In the most notable example of this issue, several investigators have demonstrated that neuroticism is consistently related to somatic complaints, even in the absence of actual illness (Costa & McCrae, 1985a, 1987; Watson & Pennebaker, 1989) If the personality characteristic under consideration is associated with neuroticism and if the disease endpoint studied wholly or even partly reflects illness behavior rather than objectively documented disease, then this interpretive ambiguity arises; the association observed might involve personality traits and actual illness, or personality and illness behavior Given this concern and its potential negative impact on the identification of robust causal influences on actual illness, symptom reports and other illness behaviors are no longer considered an acceptable operational definition of illness Although illness behaviors are important topics for research, cumulative progress in the study of personality traits as risk factors requires less ambiguous methodologies A second major development in this literature is the recognition that the pathophysiology of the major diseases studied varies considerably across The resulting delays in receipt of needed care could have deleterious consequences (Jensen, 1987; Weinberger, 1990) To date, the interpersonal impact of the repressive style has not been discussed at length in this literature If subsequent epidemiological research suggests that this trait indeed contributes to illness, then transactional stress moderation mechanisms (such as the interpersonal correlates of repressive coping) might be explored Other Traits Several other personality characteristics have figured prominently in the recent research in this area However, the corresponding literatures lack the degree of epidemiological evidence regarding their health relevance that exists for the traits reviewed thus far Clearly, Kobasa's (1979) description of psychological hardiness was a major impetus in the resurgence of interest in personality and health (Suls & Rittenhouse, 1987) In her framework, individuals characterized by an internal locus of control, a tendency to view major life changes as challenges rather than threats, and a sense of commitment in the major activities of their lives were hypothesized to be more resilient when exposed to stressful life circumstances Several studies found predicted associations among self-report measures of hardiness, life stress, and symptom reports (see Funk, 1992, for a review) Further, several studies demonstrated the predicted stress moderation effect on psychophysiological responses to laboratory stressors (Allred & T W Smith, 1989; Contrada, 1989; Wiebe, 1991) Other studies found evidence of effects of hardiness on self-reported health that were mediated by health behavior (Wiebe & McCallum, 1986) However, the degree of overlap between measures of hardiness and N/NA raised questions about the extent to which an association between emotional distress and somatic complaints accounted for much of the relevant findings (Funk, 1992; Funk & Houston, 1987), and some evidence has been consistent with this view (e.g., P G Williams, Weibe, & T W Smith, 1992) Thus, although the conceptual impact of this model on the developing field has been considerable, compelling evidence that hardiness influences actual physical health is scarce Power motivation is another trait studied as a potential risk factor (Jemmott, 1987) Defined as the desire to have an impact on others by controlling, influencing, or even helping them (McClleland, 1979), power motivation has been found to be concurrently associated with high blood pressure, and to predict the later development of essential hypertension in a 20 year prospective study of 79 initially healthy young men (McClelland, 1979) This trait, assessed by responses to the Thematic Apperception Test (Jemmott, 1987), has also been linked to reports of illness and immunosuppression (Jemmott et al., 1983; Jemmott et al., 1990; McClelland, Alexander, & Marks, 1982; McClelland, Floor, Davidson, & Saron, 1980; McClelland & Jemmott, 1980) As previously discussed, individual differences in social dominance have been found to be related to the development of Cm in both human (Houston et al., 1992) and animal research (Manuck et al., 1995) Further, attempts to influence or control others elicit the type of cardiovascular reactivity hypothesized to contribute to CHD (T W Smith, Allred, Morrison, & Carlson, 1989; T W Smith et al., 1996; T W Smith, Nealey, Kircher, & Limon, 1997) Thus, the limited yet provocative research on power motivation might be seen as another indication of the potential usefulness of further study of the vertical axis of the interpersonal circumplex as an influence on health Finally, although most of the research related to the health consequences of traits in the current prevailing personality taxonomies has focused on hostility, emotional distress, and to a lesser extent dominance, recent evidence suggests that conscientiousness and openness to experience may be important as well In an additional analysis of childhood predictors of longevity, H S Friedman and his colleagues (1993) reported that conscientiousness, as rated by parents and teachers, was associated with greater longevity Subsequent research indicated that although conscientiousness is associated with positive health behaviors (BoothKewley & Vickers, 1994), the beneficial effects of this trait on longevity could not be accounted for by the mediating effects of health behaviors, including reduced alcohol consumption, nonsmoking status, prudent diet, or avoidance of accidents and violence (H S Friedman, Tucker, Reise, 1995) Curiosity-a component of openness to experience- has been found to predict increased survival over a 5-year follow-up of older adults, a result that could not be attributed to other known medical or behavioral risk factors (Swan & Carmelli, 1996) CONCLUSIONS AND FUTURE DIRECTIONS As noted at the outset of this chapter, the literature on personality and health contains some areas of cumulative progress but some unresolved problems as well These concluding sections summarize the emerging findings, outline the limitations, and suggest some directions for maximizing the yield of future studies Do Personality Traits Predict Subsequent Illness? Despite the conclusions of previous critiques of research in this area (e.g., Angel, 1985), there is clear evidence that personality traits indeed predict objective health outcomes Quantitative and qualitative reviews have summarized evidence that hostility and the TABP are associated with “hard” signs of CHD (i.e., MI and SCD) and reduced longevity (Adler & Matthews, 1994; T Q Miller et al., 1991, 1996) These effects are statistically small, but given the scope and impact of the health outcomes examined, they are important contributions to an understanding of threats to public health The results of several large, prospective studies examining objective health outcomes suggest that this relation does not reflect the effects of personality traits on simple illness behavior, and it does not reflect the effects of illness on personality The literature on the health effects of neuroticism or negative affectivity is more complex than it was even a few years ago Although chronic negative emotions, such as anxiety and depression, are clearly associated with illness behavior in the absence of disease (Stone & Costa, 1990; Watson & Pennebaker, 1989), recent evidence suggests a more substantial role as well Considered either as an individual difference within the range of normal variation, or as a diagnosable emotional disorder, chronic negative affect has been found to predict objective health outcomes in initially healthy samples and among patients with established disease This area of research might benefit from an updated quantitative review to examine the level of inconsistency and possible causes among the independent studies available The tentative review suggests that this trait is a potentially important influence on health However, there are negative results from large, wellcontrolled prospective studies Further, the circumstances under which N/NA contributes to illness behavior as opposed to actual illness remain to be identified (C Smith, Wallston, & Dwyer, 1995) The evidence that pessimism influences health is intriguing and suggestive, but is somewhat more limited than is the case for hostility or negative affectivity The clarification of methodological issues in previous research on this trait should pave the way for more definitive studies, and the accumulating evidence suggests that such studies would be worthwhile Finally, despite its central place in the personality and health literature, the evidence that repressive coping contributes to illness is limited to a small number of studies, and some of them used personality measures of undocumented validity Repressive coping with anger (i.e., anger suppression or “anger-in”) may be unhealthy, but this might reflect more general consequences of trait anger Thus, conclusions about the effect of repressive coping on health will require several additional, methodologically sophisticated studies Although there is clear evidence of a reliable association between some personality traits and illness, several interpretive ambiguities remain even in the areas with consistent results The degree of information about the personality trait(s) actually assessed by the measures used in this research varies considerably As a result, it is sometimes unclear as to the specific psychological characteristic(s) involved in the effect Second, given the correlational nature of even the prospective designs, the possibility that biologic, psychologic, or socioeconomic third variables account for the observed covariation between personality traits and disease must be acknowledged Finally, even if it is assumed that the observed associations indicate causal effects of personality traits on health, the mechanisms through which these influences might operate are only tentatively identified (Krantz & Hedges, 1987) Importantly, animal models permit more direct evaluation of some of the central causal hypotheses and specified mechanisms, and the results of that work support the models already outlined (e.g., J R Kaplan et al., 1994; Manuck et al., 1995) Is There a Disease Prone Personality? An influential review of the personality and health literature suggested that individuals characterized by chronic negative affect displayed a disease prone personality (H S Friedman & Booth-Kewley, 1987) Although the basis of that conclusion was criticized appropriately on methodological grounds (Matthews, 1988; Stone & Costa, 1990), the subsequent research has indicated that the conclusion might have merit However, the evidence regarding the unhealthy effects of chronic hostility, anger, and disagreeable behavior is more compelling Therefore, the earlier description of a disease prone personality underemphasized an important personality trait-agreeableness versus antagonism in the five-factor model, or friendliness versus hostility in the interpersonal variation of this taxonomy Neuroticism and antagonism are independent traits, but obviously co-occur such that people with high levels of both characteristics are described not only as distressed, cold, and hostile, but selfish and intolerant as well (Saucier, 1992) Thus, this combination of chronic distress and disagreeable social behavior might constitute a disease prone personality Are There Other Personality Risk Factors? The five-factor model and the interpersonal variation of this taxonomy suggest that the current research on personality risk factors might be expanded The provocative findings in which conscientiousness and openness to experience predicted longevity (H S Friedman et al., 1993; Swan & Carmelli, 1996) were discussed earlier These dimensions should be pursued in additional research Similarly, some evidence from epidemiological studies suggests that social dominance might be a second facet of the TABP that confers risk of CHD and measure mortality (Houston et al., 1992, 1997), and this finding has an important parallel in nonhuman primate research on psychosocial influences on CAD (Manuck et al., 1995) Thus, the vertical axis of the interpersonal circumplex should also be examined in future research There are two dimensions that not fall clearly within the current personality taxonomies that might be useful in future studies The first dimension, discussed from several perspectives, involves social and emotional competence The concept of social intelligence (Cantor & Kihlstrom, 1987) lies at the intersection of personality and traditional definitions of intelligence This construct refers to the “declarative and procedural knowledge that individuals bring to bear in interpreting events and making plans in everyday life situations” (Cantor & Kihlstrom, 1987, p 3) Consistent with the cognitive- social approach to personality described earlier (Cantor, 1990; Mischel & Shoda, 1995), this model emphasizes the processes underlying individuals' construal of situations, the goals they pursue, and the flexibility and effectiveness of the strategies they employ in those pursuits Further, individuals vary in their social “expertise” in specific contexts, such as vocational achievement or personal relationships Emotional intelligence (Mayer & Salovey, 1995) is a somewhat more circumscribed construct, referring to competence in identifying and regulating emotions in oneself and others Another closely related concept with greater similarity to traditional descriptions and assessments of personality traits is ego- resiliency (Block & Kremen, 1996; Klohnen, 1996) Although broad individual differences in social and emotional competence are difficult to describe and measure, it is apparent that persons differ in the extent to which they have the skills or competence to succeed in important life tasks A further implication is that many life tasks will be particularly difficult for individuals with less expertise, with the likely result of increased stress Consistent with the general view of the psychophysiology of stress as a link between personality traits and illness, limitations in social intelligence or competence could confer vulnerability to disease Thus, the study of personality traits as risk factors might be expanded to include increased attention to skill and adaptive competencies, especially in emotional and social domains (Ewart, 1991; 1994) The second health relevant dimension that falls outside traditional taxonomies is social support Social support is clearly associated with reduced risk of physical illness and increased longevity (Adler & Matthews, 1994; Be&man, 1995; S Cohen, Doyle, Skoner, Rabin, & Gwaltney, 1997; Hazuda, 1994; Orth-Gomer, 1994) Further, low support is associated with the pathophysiological mechanisms believed to link psychosocial processes to illness (Uchino et al., 1996) Although the traditional view of this construct is that it represents characteristics of the social environment (S Cohen & Wills, 1985), recent evidence suggests that social support might be more accurately conceptualized as a characteristic of the person For example, social support is closely related to other stable personality characteristics including shyness, neuroticism, anxiety, and depression (e.g., B Sarason, Shearin, Pierce, & I G Sarason, 1987; I G Sarason, Levine, Basham, & B Sarason, 1983) Further, perceptions of social support appear to be stable over time (Newcomb, 1990; I G Sarason, B Sarason, & Shearin, 1986), and to remain consistent across settings (Lakey & Lewis, 1994) Finally, perceptions of social support seem to be heritable to some extent, with genetic factors accounting for as much as half or more of variance in support perceptions (Kendler, 1997; Plomin, Reiss, Heatherington, & Howe, 1994) Thus, rather than conceptualizing and studying social support as something distinct from the personality traits identified as risk factors, a person-focused alternative view of social support might be useful (Pierce, Lakey, I G Sarason, B Sarason, & Joseph, 1997) Better still, models and methodological strategies that integrate social and personality characteristics hold particular promise It may be that low social support and limitations in social intelligence or competence can be described, at least in part, through combinations of traits in the current personality taxonomies (e.g., low agreeableness, high neuroticism) However, related research and theory suggest that these processes probably cannot be simply reduced to those variables As a result, a somewhat broader view of the array of health relevant individual differences could add to the understanding of the ways in which personality can influence health Can We Make Better Use of Personality Psychology? The discussion thus far illustrates how consideration of current personality taxonomies such as the five-factor model can provide much needed conceptual organization to this area of research These taxonomies also point to some traits that might have been neglected in the area Further, the related assessment devices and the psychometric tradition in which they are embedded can facilitate the evaluation and refinement of key measures of traits studied as predictors (Costa & McCrae, 1987a; H S Friedman et al., 1995; Marshall et al., 1994; T W Smith & P G Williams, 1992) The second major emphasis in current personality psychology- the cognitive-social and interpersonal perspectives- also could make a major contribution to the study of personality traits as risk factors As discussed earlier, these perspectives can be useful in identifying the mechanisms underlying the broad elements in trait taxonomies (e.g., Graziano, JensenCampbell, & Hair, 1996), as well as the psychological processes through which traits influence pathophysiology Further, the constructs identified in these models (e.g., appraisal, coping strategies, social competencies, etc.) can be easily incorporated in the design of interventions However, perhaps a more far-reaching implication of the cognitive-social and interpersonal conceptualizations of personality is the blurring of the commonly held distinction between risk factors considered characteristics of the person (e.g., hostility) and those that are traditionally considered characteristics of the social environment (e.g., social support) The reciprocal relation between persons and social circumstances is a fundamental assumption of these models (Wagner et al., 1995), as is the assumption that these reciprocal patterns are evident over periods of many years (e.g., Caspi et al., 1989) and in specific, time-limited interactions (T W Smith, 1995) These assumptions pose a challenge to conceptualize risk without simple distinctions between personality and the social environment From this dynamic interactional perspective, risk is conferred not through specific personality traits, but through recurring transactions between persons and social environments (Revenson, 1990; T W Smith, 1995), such as the model of how hostility influences health presented in Fig 9.7 In this elaboration of the previously discussed transactional model, hostile persons recurrently construct social circumstances that are both unhealthy (i.e., low in support and high in strain), and that maintain their own hostile interactional style Hostility can be accurately described through the traits in personality taxonomies (i.e., low agreeableness and high neuroticism), but the “active ingredients” through which hostile persons create such an environment consist of the cognitive and behavioral processes identified in cognitive-social models of personality Clearly, the description of the risk process linking hostility and health is incomplete without attention to the social context of hostility In addition, the understanding of low support and high social strain as risk factors would be incomplete without attention to the ways in which individuals create and maintain those circumstances The interpersonal perspective in personality and clinical psychology may be of particular use in this reconceptualization of psychosocial risk The interpersonal circumplex (see Fig 9.1 ) provides a common conceptual and measurement framework for describing personality characteristics, social stimuli, and interactional behaviors (Benjamin, 1994; Kiesler, 1991; Wiggins, 1991) For example, both the personality trait of hostility and the environmental variable of social support can be located along the horizontal axis of the circumplex Further, this perspective provides detailed models and assessments of the transactional processes linking persons and social contexts (Benjamin, 1994; Kiesler, 1996; Wagner et al., 1995) Although the conceptual and perhaps treatment implications of the transactional view are clear, the implications of this model for epidemiological research are less obvious Evidence from large prospective studies of personality and subsequent health is a critical component of research in this area Simply put, nobody would pursue research on the traits without evidence that they predict objective health outcomes Yet, typical analytic strategies in psychosocial epidemiology not accommodate this reciprocal view of personality and social risk factors Current practice in epidemiological studies of psychosocial risk factors reflects the traditional strategy of evaluating independent predictive utility, such as determining if smoking and blood pressure have statistically independent effects on CHD Given that the causal processes through which psychosocial factors influence health may involve substantive relations among psychosocial characteristics, the practice of forcing statistical independence on naturally confounded variables seems likely to provide an inaccurate assessment of risk That is, the traditional approach of examining statistically independent risk factors removes personality traits from essential elements of the surrounding social context (Revenson, 1990) Yet, in the transactional view, it is precisely this dynamic interaction of traits with contextual factors that influence the pathophysiology of disease An alternative analytic strategy would classify individuals in terms of naturally occurring patterns of personality and environmental characteristics, thereby providing a closer correspondence between specific statistical hypotheses and the transactional conceptual hypotheses about risk (Gallo & T W Smith, 1999) That is, multiple features of the hypothesized recurring cycles of personality-social environment transaction could be assessed and used to identify high and low risk groups (Wagner et al., 1995) For example, the global personality traits or even middle units of personality listed in Fig 9.7 could be assessed along with the social environmental characteristics to which they are reciprocally related Cluster analytic techniques could then be used to describe specific patterns of personality and social risk (Gallo & T W Smith, 1999), and included as predictors of subsequent health in prospective studies Such naturally occurring groupings might reflect common adaptive and maladaptive interactional styles Are There Applications of Personality-Health Research? The potential health benefits of modifying personality traits identified as risk factors are illustrated by the results of the RCPP described earlier (M Friedman et al., 1984; Powell & Thoresen, 1988) Enduring personality characteristics can be modified, and at least in that instance seemed to have had important consequences for subsequent health Anger and hostility are amenable to treatment (Deffenbacher, 1994), as are other negative affects such as anxiety and depression (Chambless & Gillis, 1993; Hollon, Shelton, & Davis, 1993) Further, preliminary studies suggest such treatments may have positive effects on health (Gidron, Davidson, & Bata, 1999) Given the status of the related literatures, larger controlled trials examining the health benefits of interventions addressing these characteristics are justified, especially in high risk populations such as postinfarction patients The personality and health literature also has implications for primary prevention efforts If traits such as (low) agreeableness and high neuroticism contribute to illness, then development of social and emotional adjustment and competencies should reduce risk Attempts to prevent emotional disorders, antisocial behavior, and substance abuse in children and adolescents often focus on traits and processes that are similar to those discussed in models of the personality characteristics that confer risk of physical illness (Blechman, 1996; Blechman, Prinz, & Dumas, 1995; Caplan et al., 1992; Greenberg, Kusche, Cook, & Quamma, 1995; Tolan, Guerra, & Kendall, 1995) These prevention programs attempt to foster emotional selfregulation and social interaction competencies through educational methods These interventions generally produce improved emotional adjustment, peer relations, and conflict resolution skills Although targeted toward mental health, this primary prevention technology may have beneficial effects on physical health as well Thus, a final conclusion from the current research on personality traits as risk factors for physical illness is that the existing literature on primary prevention in the domain of social and emotional health may have valuable implications for the prevention of physical illness Efforts to maximize the emotional and social adjustment of children and adolescents may contribute to their later physical health as adults