Coping, Locus of Control, Social Support, and Combat-Related Posttraumatic Stress Disorder: A Prospective Study

Journal of Personality and Social Psychology 1988, Vol. 55, No. 2,279-285 Copyright 1988 by the Amerkan Psychological Association, Inc. 0022-3514/88/$00.75 Coping, Locus of Control, Social Support, and Combat-Related Posttraumatic Stress Disorder: A Prospective Study Zahava Solomon, Mario Mikulincer, and Ehud Avitzur Department of Mental Health Israel Defense Forces Medical Corps We examined the relations between coping, locus of control, and social support and combat-related posttraumatic stress disorder (PTSD). The sample consisted of 262 Israeli soldiers who suffered a combat stress reaction episode during the 1982 Lebanon war and were followed 2 and 3 years after their participation in combat. Cross-sectional analyses revealed significant relations between locus of control, coping, and social support and PTSD at the two points of assessment. Changes in PTSD from Time 1 to Time 2 were also associated with changes in coping. We discuss theoretical and methodological implications of the findings. Participation in combat places soldiers under intense pressures that can impair their functioning (drinker & Spiegel, 1945). The most widespread manifestation of psychopathology on the battlefield is combat stress reaction (CSR), also known as battle shock and battle fatigue. CSR is characterized by psychomotor retardation, withdrawal, increased sympathetic activities, stuttering, confusion, nausea, vomiting, and paranoid reactions (Grinker & Spiegel, 1945). The common element in all of these varied manifestations is that soldiers cease to function efficiently from a military viewpoint and may even endanger themselves and their comrades. It has been demonstrated that combat stress has potential long-lasting effects that leave soldiers emotionally vulnerable (Solomon, Weisemberg, Schwarzwald, & Mikulincer, 1987). The most common disorder observed among CSR casualties is posttraumatic stress disorder (PTSD). PTSD is characterized by reexperiencing the traumatic event; numbing of responsiveness to or reduced involvement with the external world; and a variety of autonomic, dysphoric, or cognitive symptoms (Diagnostic and Statistical Manual of Mental Disorders Third Edition [DSM-III]; American Psychiatric Association, 1980). Solomon et al. (1987) found that among a sample of CSR casualties of the 1982 Lebanon war, 59% had PTSD 1 year after war. In light of the prevalence of PTSD, the question of what factors are involved in its development is a naturally asked one. In this study we examined the impact of coping style, locus of control, and social support on the course of PTSD among CSR casualties. Locus of Control Personal Resources Locus of control is defined as internal when individuals tend to attribute environmental events to themselves and as external Zahava Solomon is also at Tel-Aviv University, School of Social Work. Mario Mikulincer and Ehud Avitzur are at Bar-Ilan University, Department of Psychology. Correspondence concerning this article should be addressed to Zahava Solomon, Department of Mental Health, Medical Corps, Israel Defense Forces, Military P.O. Box 02149, Israel. when individuals attribute such events to things outside their power (Lefcourt, 1976; Rotter, 1966; Strickland, 1978). Strickland suggested that internal locus of control, as compared with external locus, improves health because it is associated with preventive behavior, efforts to improve functioning, and greater resistance to psychological dysfunctions. Most of the research supports Strickland's view: In contrast to people with external locus of control, people with internal locus of control express greater motivation to take inoculations (Debbs & Kirscht, 1971), tend more to use safety belts when driving (Williams, 1972a), are more likely to have regular dental examinations (Williams, 1972b), are more successful in weight-reduction programs (Balch & Ross, 1975), and more often obey doctor's orders and persist in required medical treatment (Strickland, 1978). In the area of mental health, it has been found that people with internal locus of control suffered less from severe psychiatric disorders (Lefcourt, 1976), especially from chronic depression (Abramson, Seligman, & Teasdale, 1978). In light of these findings, one could hypothesize that in CSR casualties with internal locus of control, PTSD will be less severe than in casualties with external locus of control. Coping Styles Coping consists of the cognitions and behaviors that people use to assess and reduce stress and to moderate the tension that accompanies it (Billings, Cronkite, & Moos, 1983). In other words, coping is behavior designed to fill two functions: (a) a problem-focused function channeling resources to solve the stress-creating problem and (b) an emotion-focused function easing the tension aroused by the threat by intrapsychic activity, such as denying or changing one's attitude toward the threatening circumstances (Lazarus & Lounier, 1978). Researchers have found that people tend to combine these two types of coping in accordance with the context and the specific problem with which they are dealing (Folkman & Lazarus, 1985; Pearlin & Schooler, 1978), as well as with their personalities (Folkman & Lazarus, 1980). Folkman (1984) and Mitchell, Cronkite, and Moos (1983) 279

280 Z. SOLOMON, M. MIKULINCER, AND E. AVITZUR proposed that the optimal coping style consists of the largest possible repertoire of coping responses. Even if intrapsychic coping aids in maintaining emotional balance, the nonuse of problem-solving strategies will in the end have negative psychological outcomes. Indeed, people who are depressed tend to use intrapsychic coping at the expense of instrumental coping, whereas among relatively healthy people, the dominant style of coping is problem solving (Billings & Moos, 1981; Fblkman & Lazarus, 1980; Pearlin & Schooler, 1978). On this basis, one could hypothesize that among CSR casualties, a coping style that emphasizes problem-solving coping will be associated with less PTSD, whereas a coping style that emphasizes intrapsychic coping will be associated with more severe PTSD. Social Resources A great deal of research has been conducted on the relation between social support, endurance under stress, and psychiatric disturbance (for a review, see Leavy, 1983). All of those researchers essentially tested the supposition that the absence of social support in stressful situations may increase the vulnerability of individuals to illnesses associated with exposure to stress (Cobb, 1976; Hobfoll & Walfish, 1984). Some claimed that the absence of social support is a stress factor in and of itself that may create psychological disturbances. A number of studies have actually shown that subjects who have a good deal of social support are less vulnerable to psychological disorders (Cobb, 1976; Cohen & McKay, 1984; Gottlieb, 1978; Holahan &Moos, 1981). Social support has been shown to be related to favorable mental health outcome following combat stress. Keane, Scott, Chavoya, Lamparski, and Fairbank (1985) found that Vietnam veterans suffering from PTSD reported a decline in social support from the time of their discharge to the present. Assessing stress reactions following the 1982 Lebanon war, Hobfoll and London (in press) found that exposure to war-related stress led to emotional distress, especially among those veterans with low social support. On this basis, one could hypothesize that in CSR casualties with high social support on returning home, the course of long-term PTSD will be more positive than in casualties with low social support. Lefcourt, Martin, and Saleh (1984) and Sandier and Lakey (1982) suggested that there is a relation between people's locus of control and the effectiveness of the social support they receive. Those researchers found that social support was more effective in mediating stress among people with internal locus of control than among those with external locus of control. Their explanation for this difference is that people with internal locus of control use the social support they receive instrumentally, such as to obtain information that may help them overcome the stressors, whereas people with external locus of control use their social support in a less instrumental manner. On this basis, one could hypothesize that the impact of social support on the course of PTSD will be stronger in people with internal locus of control than in those with external locus of control. Overview The purpose of this research was to assess the impact of personal and social resources on the development of PTSD among CSR casualties. The studies conducted up until now that have related personal and social variables to psychiatric disturbances were carried out at a single or almost single point in time, and for this reason the variables cannot be regarded as being causally related to the outcome (Mitchell et al., 1983). In contrast, our research was longitudinal. It focused on two points in time: 2 years (Time 1) and 3 years (Time 2) following combat. We examined (a) the relation between personal resources and social support and PTSD at each point in time and (b) the relation between changes in the course of PTSD and changes in both personal and social resources. Subjects Method Subjects were sampled from the population of soldiers who fought on the front line during the Lebanon war (1982) and were identified by Israel Defense Forces (IDF) mental health personnel as CSR casualties. We define CSR here as behavior by a soldier in combat that is interpreted by experienced clinicians as signaling that the soldier has ceased to function as a combatant. Criteria for inclusion in our sample were (a) participation in frontline battles during the Lebanon war; (b) a referral for psychiatric intervention made by the soldier's battalion surgeon during the war, (c) a diagnosis of CSR made on the battlefield by IDF clinicians trained and experienced in the diagnosis of combat-related reactions; (d) no indication in the clinicians' reports of serious physical injury; and (e) no indication in the clinicians' reports of other combatrelated disorders, such as brief reactive psychosis or fictitious disorders. The research staff determined eligibility by using records of clinicians' diagnoses made on the battlefield. The sample was composed of 262 male soldiers who were checked 2 years after the 1982 Lebanon war (78% of the sample chosen). These soldiers were also checked 3 years after the war. Follow-up efforts at Time 2 were successful in locating 186 soldiers, who represented 71% of the sample at Time 1. Data retrieved from military records and from the questionnaires completed at Time 1 revealed that soldiers who participated at both points of time did not significantly differ from those who declined to participate at Time 2 in their demographic and military background, premilitary adjustment, or intelligence. The majority of the subjects (66%) were bora in Israel. Twenty-four percent were of African or Asian origin and the remainder (10%) of European or American descent. Approximately two thirds (64%) were married. Seventy-one percent of the subjects ranged in age from 18 to 33 years; 29% were above age 33 (median age 29). Nineteen percent of the subjects had completed eighth grade, 28% had had at least some high school, 34% had completed high school, and 17% had studied beyond high school. Thirty two percent were draftees doing their 3 years of mandatory military service, and 68% were reserve soldiers. Measures Post- Traumatic Stress Disorder (PTSD) Inventory. The PTSD Inventory consists of 13 statements describing the DSM-III symptoms of PTSD as adapted for war trauma. Respondents were asked to indicate whether they had experienced each of the described disturbances within the past month. Internal consistency among the 13 items was high (Cronbach's alphas were.86 for Time 1 and.88 for Time 2, respectively). The number of positively endorsed symptoms (PTSD severity) was then calculated by counting the positive responses on the 13 items (for detailed information about reliability and concurrent validity of the PTSD Inventory, see Solomon et al., 1987). The 13 statements were divided into three categories of symptoms corresponding to the three DSM-III criteria for the diagnosis of PTSD: (a) recurrent and intensive recollections of the traumatic event (3

RESOURCES AND POSTTRAIJMATIC STRESS DISORDER 281 items); (b) numbing of responsiveness to or reduced involvement with the external world (3 items); and (c) additional symptoms (7 items), including hyperalertness, sleep disturbance, survivor guilt or guilt feelings about behavior during the war, memory or concentration difficulties, avoidance of activities that trigger recall of the event, and intensification of symptoms with exposure to events that symbolize the trauma. Locus of control. Control expectancies were assessed by a shortened version of Rotter's Internal-External Locus of Control Scale (Rotter, 1966). We used a Hebrew version that consisted of the most reliable 15 items. Internal consistency among the items was acceptable (Cronbach's alphas were.72 for Time 1 and.73 for Time 2, respectively). The Internal-External Expectancy score reflected the number of internal answers on the 15 items. Coping style. Coping was assessed with a 44-item scale that is a shortened version of the Ways of Coping Checklist reported by Folkman and Lazarus (1980). The 44-item self-report measure retains the broad range of cognitive and behavioral strategies people use to deal with stressful events. In this study, the 44-item scale was translated into Hebrew by three highly experienced bilingual psychologists and further pretested in a small sample of soldiers. In this study, respondents were asked to recall stressful episodes that had taken place in the past 3 months. The subjects were presented with the 44-item scale. For each item, they were asked to indicate on a 4- point Likert scale (1 = not used, 4 = used a great deal) to what extent they tend to act in the way described when confronted with the stressful event. In order to determine the factor structure of the instrument, factor analyses with varimax rotation were performed separately for Time 1 and Time 2 data. For both points of time, a four-factor solution yielded the most conceptually interpretable set of factors (66% of explained variance for Time 1 data and 54% for Time 2 data). However, there are differences between Time 1 and Time 2 in the loadings of particular items in each factor. These differences made it difficult to compute factor scores with a common metric across the two times. Thus, we pooled observations across the two times and performed a new factor analysis on the pooled sample. This factor analysis also yielded four interpretable factors (62% of explained variance) that generally resembled those obtained in the analyses of Time 1 and Time 2 data. On the basis of this last analysis, we computed four scores by averaging items that loaded higher than.40 in a factor. These four scores, similar to those reported by Folkman and Lazarus (1985), were characterized as follows: 1. Problem-Focused Coping: This factor explained 37% of the variance and included 15 items, such as "I try to analyze the problem in order to understand it better." Cronbach's alphas for the 15 items were.88 for Time 1 and.90 for Time 2. 2. Emotion-Focused Coping: This factor explained 10% of the variance and included 12 items, such as "wish that I can change how I feel," "try to look in the bright side of things," and "criticize myself." Cronbach's alphas for the 12 items were.82 for Time 1 and.88 for Time 2. 3. Seeking Social Support: This factor explained 8.7% of the variance and included 8 items, such as "talk to someone to find out more about the situation." Cronbach's alphas for the 8 items were.86 for Time 1 and.86 for Time 2. 4. Distancing: This factor explained 6.8% of the variance and included 5 items, such as "I try to forget the whole thing." Cronbach's alphas were.74 for Time 1 and.76 for Time 2. Social support scale. The current social support questionnaire was devised in our laboratory on the basis of Mueller's (1980) social network interview. Subjects received seven questions regarding expressive and instrumental support (e.g., emotional help, financial support) that they received from their network's members (e.g., family members, friends, acquaintances). Respondents were asked to indicate in a 4-point Likert scale (1 = not at all, 4 - very much) to what extent theyreceivedsupport from their network's members. Cronbach's alphas for the seven items were.84 for Time 1 and.88 for Time 2, indicating high internal consis- Table 1 Stability and Changes in PTSD Intensity, Coping Style, Locus of Control, and Social Support Between Time 1 and Time 2 Variable PTSD intensity Personal resources Locus of control Coping Problem focused Emotion focused Searching for help Distancing Social support Time 1 Time 2 Stability coefficient M SD M SD.60**.65**.58**.55**.38**.40**.67** 6.44 5.54 3.03 2.71 2.97 2.50 2.81 3.72 2.68 0.67 0.62 0.69 0.68 0.74 5.01 6.02 2.97 2.49 2.94 2.42 2.92 3.94 2.57 0.68 0.68 0.72 0.69 0.79 5.70** -2.81** 1.83 4.66** 0.89 1.48-2.19* Note. Entries for stability coefficients were Pearson correlation coefficients between the measurements at the two points of time. */i<.05.**r><.01. tency. Thus, the total score of social support was calculated by averaging answers subjects gave to the seven questions. Procedure Subjects were asked twice to report to the headquarters of the surgeon general of the IDF approximately 24 and 36 months following their participation in battle. The request was accompanied by a personal letter explaining that they had been selected randomly to participate in a routine health assessment conducted as part of the Medical Corps' concern for the well-being of its soldiers. Prior to filling out the questionnaires, the subjects were assured that the data would remain confidential and would in no way affect their status in military or civilian life. Subjects were seated in groups of 7 to 19 and individually filled out a battery of questionnaires. Statistical Analysis Results The statistical analysis was composed of three parts: The first consisted of stability analyses of the measures at the two points of time. The second consisted of cross-sectional analyses in order to discover the relations between PTSD and the personal and social resource variables at each point of time. The third examined the relation between the possible temporal changes in the PTSD and in the various personal and social resources. Stability Analysis of the Measurements The stability of each measure was calculated by a Pearson correlation coefficient. The direction and significance of the changes that took place between the two points of time were assessed by a t test for pairs. The relevant results of the stability analysis are presented in Table 1. The stability coefficient for the intensity of PTSD was statistically significant, and the t test showed that fewer PTSD symptoms were endorsed in Time 2, J(185) = 5.70, p <.01, than in Time 1. The stability coefficients of the coping scales and locus of control were high. There was a general trend toward lower scores in all four coping factors between Time 1 and Time 2, but the decline was significant only in emotion-focused coping,

282 Z. SOLOMON, M. MIKULINCER, AND E. AVITZUR Table 2 Multiple Regression for Predicting PTSD Intensity at Time 1 on the Basis of Coping, Locus of Control, and Social Support Variable r ff t Personal resources Locus of control Coping Problem focused Emotion focused Searching for help Distancing Social support */><.05. **;><.01. -.38" -.21*.42**.03.15 -.43** -.09 -.11.36 -.07.05 -.25-1.04-1.24 4.07** -0.76 0.64-2.99** t( 185) = 4.66, p <.01. The change in the locus of control, which became more internal, was also significant, t( 185) = -2.81, p <.01. The stability coefficient for social support was also high. There was a significant trend toward improvement in the availability of social support from Time 1 to Time 2, t(\ 85) = -2.19, p<.05. Cross-Sectional A nalyses In order to examine the simultaneous relationships among personal and social resources and the intensity of PTSD, we conducted the following tests for each year separately: (a) Pearson correlation coefficients were calculated between the intensity of PTSD and each of the personal and social resources, (b) A simultaneous multiple regression was carried out for all of the independent variables as predictors of the intensity of PTSD. (c) A hierarchical regression analysis assessing the contribution of the interaction between locus of control and social support to PTSD, controlling for the main effects of locus of control and social support, was conducted. The results for Time 1 are presented in Table 2 and for Time 2 in Table 3. Cross-sectional analysis for Time 1. The correlation coefficients show clear relations between personal and social resources and the intensity of PTSD. Emotion-focused coping was positively associated with the intensity of PTSD, whereas problem-focused coping was negatively associated with PTSD intensity. Locus of control was found to be negatively associated with PTSD intensity: The more internal the locus of control, the less intense the PTSD. Social support was also found to be associated with the intensity of the PTSD, with greater social support associated with less intense PTSD. The simultaneous multiple regression analysis indicated that social and personal resources explained 33.4% of the variance of PTSD intensity, F(6, 141)= 11.77, p<.01. Social support and emotion-focused coping were the only two variables that were statistically significant, because of the redundancy among the independent variables. The remaining variables contributed only marginally to explaining the PTSD variance. In order to examine the hypothesis regarding the interactive influence of locus of control and social support on PTSD intensity, we calculated an interaction term by means of the product of the social support and locus of control variables (Cohen & Cohen, 1975). A hierarchical regression analysis showed a nonsignificant contribution of the interaction term after the main effects for locus of control and social support were entered into the regression equation. Cross-sectional analysis for Time 2. The correlation coefficients indicated significant relations between personal and social resources and the intensity of PTSD. Emotion-focused coping and distancing were positively related to the intensity of PTSD 3 years after war. In Time 1, internal locus of control was found to be negatively associated with PTSD. Social support was also found to be related to PTSD: The greater the social support, the less intense the PTSD 3 years after war. The simultaneous multiple regression analysis indicated that social and personal resources explained 21.7% of the variance of PTSD intensity, F(6, 141) = 7.02, p <.01. Only emotionfocused coping was significant, because of the redundancy among the independent variables. In addition, a hierarchical regression analysis showed a nonsignificant contribution of the interaction between locus of control and social support to PTSD intensity. Longitudinal Analysis The longitudinal analyses had two main purposes: (a) to examine the relations between changes in personal and social resources and changes in PTSD intensity between Time 1 and Time 2 and (b) to examine the contribution of social and personal resources at Time 1 for predicting PTSD intensity at Time 2 while controlling for Time 1 PTSD. The analysis of the simultaneous changes of PTSD and resources between Time 1 and Time 2 was based on Cronbach and Furby's (1970) strategy. They suggested that a multiple regression approach can overcome statistical and methodological difficulties inherent in the measurement of change (see also Holahan & Moos, 1981). This approach made it possible to derive partial correlations between social and personal resources measures on one hand and the intensity of PTSD in Time 2 on the other while controlling for all of the variables in Time 1. These partial correlations can be interpreted as expressing the relations between the resource measures and PTSD intensity as if the subjects all had the same scores for all the variables in Time 1. For this reason, the partial correlations reflected the relations between the changes in resources and changes in PTSD intensity. The partial correlations (controlling for all Time 1 measures) between personal and social resources and PTSD intensity in Table 3 Multiple Regression for Predicting PTSD Intensity at Time 2 on the Basis of Coping, Locus of Control, and Social Support Variable r B t Personal resources Locus of control Coping Problem focused Emotion focused Searching for help Distancing Social support *p<.05.**p<.01. -.29** -.03.39**.04.20* -.31** -.13 -.13.32.06.02 -.12 1.91 0.93 8.93** 0.36 0.07 1.45

RESOURCES AND POSTTRAUMATIC STRESS DISORDER 283 Time 2 revealed that only two coefficients were significant: social support, r( 135) = -. 16, p <.05, and emotion-focused coping, r(135)=. 17, p<. 05. That is, after the variables of Time 1 were neutralized, changes in the intensity of PTSD between Time 1 and Time 2 were accompanied by changes in social support and emotion-focused coping. A partial correlation was calculated between the interaction of Locus of Control X Social Support and PTSD intensity in Time 2, controlling for all of the variables in Time 1 and for social support and locus of control in Time 2. The partial correlation was low (r =.02), indicating a lack of significant interaction. In order to examine whether the absolute level of resources at Time 1 predicted PTSD at Time 2, we performed partial correlation analyses between social and personal resources at Time 1 and PTSD intensity at Time 2 while controlling for PTSD at Time 1. These analyses allowed us to assess the contribution of resources at Time 1 to changes in PTSD over time. Partial correlation coefficients indicated that changes in PTSD between Time 1 and Time 2 were significantly associated with emotion-focused coping, r(135) =.20, p <.01, distancing, r(135) =.19, p <.01, and locus of control, r(l35) -.19, p <.01, in Time 1. According to these coefficients, a decrease in the intensity of PTSD at Time 2 was associated with more internal locus of control, less emotion-focused coping, and less distancing at Time 1. The partial correlation assessing the contribution of the interaction between locus of control and social support in Time 1 to PTSD in Time 2 was not significant. Discussion The relations among PTSD, personal resources, and social support were assessed among CSR casualties at two points of time, 2 and 3 years after the 1982 Lebanon war. Findings show that the intensity of PTSD declined between the two points of time, thus reflecting a process of recovery. In addition, locus of control became more internal, there was less emotion-focused coping, and more perceived social support. These concomitant changes raise questions about whether and to what extent the observed recovery was related to any of the personal and social resources. As hypothesized, associations were found at each point of time between PTSD intensity and personal and social resources. Both in the 2nd and 3rd years after the war, more intense PTSD was associated with external locus of control, emotion-focused coping style, and insufficient social support. Problem-focused coping was inversely related to the intensity of PTSD only in the 2nd year, whereas a coping style characterized by distancing was found to be related to PTSD intensity only in the 3rd year. In general, the extent of the association between PTSD intensity and the resources measured decreased between the two points of time. This decrease indicates that the contribution of personal and social resources to PTSD intensity declines in the course of time. The results regarding social support are consistent with earlier findings about the positive effects of social support on psychological adjustment (e.g., Holahan & Moos, 1981; Wilcox, 1981). However, note that our social support measure reflected the subjective perception of social support rather than its objective existence. Whereas some researchers have noted that perceived social support is what is important (Henderson, Byrne, & Duncan-Jones, 1981), others have argued that this confounds the environmental nature of social support (i.e., its objective existence) with personal attributes that affect perceptions (Gottlieb, in press). Regarding coping style, the results are consistent with previous findings concerning the positive relations between emotionfocused coping and affective disorders (Billings & Moos, 1981). However, note that Baum, Fleming, and Singer (1983) found that emotion-focused coping was more effective than problemfocused coping in dealing with a technological disaster. This inconsistency may be explained easily by differences in the studied contexts and psychological outcomes. In the technological disaster studied by Baum et al. (1983), there was little the subjects could have done to change things and thus problem-focused coping might have been frustrating and nonproductive. In contrast, the PTSD course studied in this study was not necessarily intractable, and problem-focused coping might well have been more productive. As Folkman, Lazarus, Dunkel- Schetter, DeLongis, and Gruen (1986) contended, "Whether or not a coping strategy results in positive outcomes depends on the demands and constraints of the context in which it is being used and the skill with which it is applied" (p. 1001). With regard to locus of control, the results present an interesting picture. At both Times 1 and 2, locus of control was significantly correlated with PTSD. However, the removal of the contributions of coping strategies and social support to PTSD variance canceled out the significance of locus of control (see regression analyses). This removal of locus of control as a contributor to PTSD derived from the significant correlation between locus of control and emotion-focused coping (.34 for Time 1 and.28 for Time 2); subjects who reported more internal locus of control also reported more frequent use of emotionfocused coping strategies. The correlation between locus of control and emotion-focused coping is consistent with Anderson's (1977) conclusions that subjects with internal locus of control use more instrumental strategies for dealing with stress and engage in less task-irrelevant self-preoccupation. Our finding points to the importance of coping strategies, which appear to be a reliable mediator of the relation between locus of control and PTSD. The hypothesis of an interaction between social support and locus of control was not confirmed. This hypothesis was based on the assumption that under stress people of internal rather than external locus of control can use better social support in order to cope more effectively with their problems (Lefcourt et al., 1984; Sandier & Lakey, 1982). In our sample this was not true. Perceived social support was negatively related to PTSD intensity independent of locus of control. This lack of interaction may in fact be due to the global nature of the current assessment of social support and to the lack of fine delineation of different patterns of support. Perhaps in the course of PTSD, internals do benefit from social support as a means to cope with problems, whereas externals benefit from the mere social affiliation and involvement. Although the cross-sectional data indicate a significant link between PTSD intensity on one hand and personal and social resources on the other, the direction of causality was unclear. However, our longitudinal analyses that examined the fluctuations of resources and PTSD between the two points of time

284 Z. SOLOMON, M. MIKULINCER, AND E. AVITZUR provided clearer indications of causality. These analyses revealed that (a) changes in PTSD intensity between the two points of time were concomitant with changes in emotionfocused coping style and social support; and (b) the level of emotion-focused coping, distancing, and locus of control in Time 1 were significant predictors of changes in PTSD over time. The findings indicate that emotion-focused coping and social withdrawal increase PTSD intensity, whereas less intrapsychic focusing and more social contacts alleviate PTSD. However, a number of methodological and conceptual problems impose certain limitations on our conclusions. One, because the subjects had PTSD prior to the start of the study, our findings cannot provide definitive evidence as to the direction of causality between resources and PTSD. Any causal link would most likely be established at the initial emergence of PTSD before the 2- and 3-year postcombat measurements used here. Once established, a mutually reinforcing relation between resources and PTSD may be expected. A second problem involves the conceptualization of emotion-focused coping. Emotion-focused coping can actually be viewed as an expression of PTSD rather than as a contributing factor. Many PTSD sufferers are overwhelmed by intrusive emotions and are excessively engaged in ruminations and thoughts related to the trauma (Horowitz, 1982). To the extent that this is the case, it is logical that PTSD casualties would be more engaged in coping with their internal state than with the external world. A third reason for the difficulty in implying a causal ordering resides in the nature of our measurement of personal and social resources. Among soldiers suffering from PTSD, personal and social resources are "retrospective" assessments based on the knowledge that one has psychiatric complications following exposure to a massive stressor. These soldiers may try to justify their psychiatric difficulties, searching for reasons for their inability to cope. Unfortunately, this is the case with most research on the stress-illness process (Folkman & Lazarus, 1985). A fourth limitation is derived from the fact that the measure of coping used in this study was the habitual repertoire of coping responses. This measure was chosen on the basis of literature that regards coping as reflecting individual styles (Billings & Moos, 1981; Pearlin & Schooler, 1978). No information was collected about the particular characteristics of the events subjects recollected when answering the questionnaire or about the subjective appraisal of those events (e.g., their importance, intensity, how much they could be changed). However, Folkman (1984) and Folkman and Lazarus (1985) suggested that coping responses are closely linked to both the objective characteristics of the event and to its subjective appraisal. To investigate such complex processes would necessitate more sophisticated research designs, which include control over events, appraisal, and coping strategies. This study did not take into account the possibility that the subjects' preferred way of coping might have been influenced by the particular events they coped with. It is thus possible that the differences in coping found in this study can be explained by differences in the kinds of problems reported by high- and low-level PTSD subjects. With regard to this issue, Solomon, Mikulincer, and Flum (1988) found that 2 years after their participation in the Lebanon war, subjects who reported more emotion-focused coping also reported more stressful life events in the year before but that after the impact of these stressful events was controlled for, the choice of coping strategies was still a significant predictor of PTSD. In short, those findings suggest that although subjects' choice of coping strategies is influenced by the events they cope with, their coping responses still have a unique contribution to the course of PTSD. In addition to these methodological and conceptual problems, the changes in PTSD from Time 1 to Time 2 can also be explained by other processes that were not assessed in our research. First of all, the process of spontaneous recovery should be taken into account in explaining changes in PTSD. There is evidence indicating the existence of spontaneous recovery from psychopathology among patients waiting for treatment (Endicott & Endicott, 1963). Of special interest is Davidson's (1979) phenomenological study about relative recovery over time of Nazi concentration camp survivors. Another possible explanation for the decline in PTSD over time is a decrease in the salience of the traumatic event. The IDF withdrew from Lebanon between the 2nd and 3rd years of our study, and this withdrawal brought about a reduction of media cues arousing memories of the war. Such a reduction of cues reminiscent of the traumatic event has been suggested to have a salutatory effect on PTSD (Horowitz, 1982). The strengths of this study are in its large sample size, its investigation of the effects of a catastrophic stress (the 1982 Lebanon war), the homogeneity of the sample regarding reactions during combat, and the use of a longitudinal design for the study of the long-term course of PTSD. Future research on the relation between personal and social resources and PTSD intensity should determine whether different types of massive stressors modify that relationship. It will also be of interest to test that relation in different populations, especially among veterans who developed delayed combat-related PTSD without experiencing psychological breakdown during battle. References Abramson, L. Y., Seligman, M. E., & Teasdale, J. D. (1978). Learned helplessness in humans: Critique and reformulation. Journal of Abnormal Psychology, 87,49-74. American Psychiatric Association. (1980). Diagnostic and statistical manual of mental disorders (3rd ed.). Washington, DC: Author. Anderson, C. R. (1977). Locus of control, coping behaviors, and performance in a stress setting: A longitudinal study. Journal of Applied Psychology, 62,446-451. Balch, P., & Ross, A. W. (1975). Predicting success in weight reduction as a function of locus of control: A unidimensional and multidimensional approach. Journal of Consulting and Clinical Psychology, 43, 119. Baum, A., Fleming, R., & Singer, J. E. (1983). Coping with technological disaster. Journal of Social Issues, 39,117-138. Billings, A. G., Cronkite, R. C., & Moos, R. H. (1983). Social-environmental factors in unipolar depression: Comparison of depressed patients and nondepressed controls. Journal of Abnormal Psychology, 92, 119-133. Billings, A. G., & Moos, R. H. (1981). The role of coping responses and social resources in attenuating the stress of life events. Journal of Behavioral Medicine, 4, 139-157. Cobb, J. (1976). Social support as a moderator of life stress. Psychosomatic Medicine, 38, 300-314. Cohen, J., & Cohen, P. (1975). Applied multiple regression/correlation analysis for the behavioral sciences. Hillsdale, NJ: Erlbaum.

RESOURCES AND POSTTRAUMATIC STRESS DISORDER 285 Cohen, S., & McKay, G. (1984). Interpersonal relationships as buffers of the impact of psychological stress on health. In A. Baum, J. E. Singer, & S. E. Taylor (Eds.), Handbook of psychology and health (pp. 253-267). Hillsdale, NJ: Erlbaum. Cronbach, L. J., & Furby, L. (1970). How we should measure "change" Or should we? Psychological Bulletin, 74,68-80. Davidson, S. (1979). Massive psychic traumatization and social support. Journal of Psychosomatic Research, 23, 395-402. Debbs, J. M, & Kirscht, J. P. (1971). "Internal control" and the taking of influenza shots. Psychological Reports, 28,959-962. Endicott, N. A., & Endicott, J. (1963). "Improvement" in untreated psychiatric patients. Archives of General Psychiatry, 9, 575-585. Folkman, S. (1984). Personal control and stress and coping processes: A theoretical analysis. Journal of Personality and Social Psychology, 46, 839-852. Folkman, S., & Lazarus, R. S. (1980). An analysis of coping in a middleaged community sample. Journal ofheahh and Social Behavior, 21, 219-239. Folkman, S., & Lazarus, R. S. (1985). If it changes it must be a process: Study of emotion and coping during three stages of a college examination. Journal of Personality and Social Psychology, 48.150-170. Folkman, S., Lazarus, R. S., Dunkel-Schetter, C., DeLongis, A., & Oruen, R. J. (1986). Dynamics of a stressful encounter Cognitive appraisal, coping, and encounter outcomes. Journal of Personality and Social Psychology, 50,992-1003. Gottlieb, B. F. (1978). The development and application of a classification scheme of informal helping behaviors. Canadian Psychological Review, 17, 126-136. Gottlieb, B. H. (in press). Social support and the study of personal relationships. Journal of Social and Personal Relationships. Grinker, R. R., & Spiegel, J. P. (1945). Men under stress. Philadelphia: Blakiston. Henderson, S., Byrne, P. G., & Duncan-Jones, P. (1981). Neurosis and the social environment. New York: Academic Press. Hobfoll, S. E., & London, P. (in press). The relationship of self-concept and social support to emotional distress among women during war. Journal of Social and Clinical Psychology. Hobfoll, S. E., & Walfish, L. (1984). Coping with a threat to life: A longitudinal study of self-concept, social support, and psychological distress. American Journal of 'Community Psychology, 12, 87-100. Holahan, C. J., & Moos, R. H. (1981). Social support and psychological distress: A longitudinal analysis. Journal of Abnormal Psychology, 90, 365-370. Horowitz, M. J. (1982). Psychological processes induced by illness, injury, and loss. In T. Millon, C. Green, & R. Meagher (Eds.), Handbook of clinical health psychology (pp. 53-68). New York: Plenum Press. Keane, T. M., Scott, W. O., Chavoya, G. A., Lamparski, D. M., & Fairbank, J. A. (1985). Social support in Vietnam veterans with posttraumatic stress disorder: A comparative analysis. Journal of Consulting and Clinical Psychology, 53,95-102. Lazarus, R. S., & Lounier, R. (1978). Stress-related transaction between person and environment. In L. A. Pervin & M. Lewis (Eds.), Perspectives in international psychology (pp. 287-327). New York: Academic Press. Leavy, R. L. (1983). Social support and psychological disorder: A review. Journal of Community Psychology, 11, 3-21. Lefcourt, H. M. (1976). Locus of control: Current trends in theory and research. New \brk: Halstead Press. Lefcourt, H. M., Martin, R. A., & Saleh, W. E. (1984). Locus of control and social support: Interactive moderators of stress. Journal of Personality and Social Psychology, 47, 378-389. Mitchell, R. E., Cronkite, R. C., & Moos, R. H. (1983). Stress, coping, and depression among married couples. Journal of Abnormal Psychology, 92, 433-448. Mueller, D. P. (1980). Social networks: A promising direction for research on the relationship of the social environment to psychiatric disorder. Social Science Medicine, 14,147-161. Pearlin, H. J., & Schooler, C. (1978). The structure of coping. Journal of Health and Social Behavior, 19, 2-22. Rotter, J. B. (1966). Generalized expectancies for internal versus external control of reinforcement. Psychological Monographs: General and Applied, 80(1, Whole No. 609). Sandier, I. N., & Lakey, B. (1982). Locus of control as a stress moderator: The role of control perceptions and social support. American Journal of Community Psychology, 10, 65-80. Solomon, Z., Mikulincer, M., & Flum, H. (1988). Negative life events, coping responses, and combat-related psychopathology. Journal of Abnormal Psychology, 97, 302-307. Solomon, Z., Weisemberg, M., Schwarzwald, J., & Mikulincer, M. (1987). Post-traumatic stress disorder among soldiers with combatstress reaction: The 1982 Israeli experience. American Journal of Psychiatry, 144, 448-454. Strickland, B. R. (1978). Internal-external expectancies and health-related behaviors. Journal of Consulting and Clinical Psychology, 46, 1192-1211. Wilcox, B. L. (1981). Social support, life stress and psychological adjustment A test of the buffering hypothesis. American Journal of Community Psychology, 9, 371-387. Williams, A. F. (1972a). Factors associated with seat belt use in families. Journal of Safety Research, 4, 133-138. Williams, A. F. (1972b). Personality characteristics associated with preventive dental health practices. Journal of American College of Dentists, 39, 225-234. Received September 12,1986 Revision received October 13,1987 Accepted December 30,1987