Temperamental variables in PTSD patients

ANXZETV 2:251-253 (1996)

TEMPERAMENTAL VARIABLES IN PTSD PATIENTS Moshe Kotler, Hagit Cohen, Michael Alex Matar, Marian Amir, Avi Bleich, and Zeev Kaplan

Key words: TPQ, PTSD, temperament, personality assessment

INTRODUCTION

METHODS

T h e diagnosis of Posttraumatic Stress Disorder (PTSD) requires the presence of a cluster of symptoms whose appearance is subsequent to, and presumed to have been caused by, the subject having “experienced, witnessed, or been confronted with an event involving death, serious injury, or a threat to the physical integrity of the self or others.” Although the traumatic event is prerequisite to the definition of the syndrome and the quality and “dose” of the event appears to influence it, there is no doubt that not everyone so exposed subsequently develops the clinical syndrome. This would suggest that for the full-blown clinical syndrome to develop there must be additional factors involved (McFarlane, 1989). The list of potential risk factors which have been suggested by retrospective analyses to predispose PTSD include: prior personal or family psychiatric illness; familial and genetic factors; traumatic childhood experiences; personality style (neuroticism) and disorders; coping abilities and styles; socioeconomic status, education, social support networks; and youth (Tomb, 1994). The association between personality-related variables and PTSD has been described (Southwick et al., 1993; Gunderson and Sabo, 1993; Schnurr et al., 1993), in terms of personality disorders or in terms of personality assessment scales, occasionally in terms of personality traits (Breslau et al., 1995), both as predisposing factors to PTSD or a consequence of it. True et al. (1993) have recently reported data that indicate that inheritance has a substantial influence on liability for PTSD symptoms. In order to explore a possible relationship between heritable temperamental factors and the PTSD syndrome, we decided to use the tridimensional personality questionnaire (TPQ), a 100-question truelfalse self-report questionnaire, designed by Cloninger (1994) to measure four distinct domains of temperament (novelty seeking, harm avoidance, reward dependence and persistence). It is h othesized that these four dimensions are associate with distinct genetic and neurochemical factors. We administered the T P Q to a group of consenting patients who fulfilled the criteria for PTSD in the PTSD clinics of three medical centers in Israel and compared their scores to American norms (Cloninger, 1994) and an Israeli norms population (Ebstein et al., 1995).

Fifty-six patients diagnosed as suffering from PTSD (DSM-111-R criteria), were recruited from the outpatient services of three medical centers in Israel. TPQs were individually administered under the guidance of a trained psychiatrist from the study team. Forty-six patients completed the T P Q fully, 40 males and 6 females, mean age 41 (k 10.3 years). All were fluent in Hebrew and had an educational level adequate to complete the questionnaire (1 1.2 2.4 years). Severity of illness, according to clinical global impression scale (CGI). mild = 10; moderate = 18; marked = 18. Type of trauma: war = 24; acts of terror = 12; car accident = 10. Mean time elapsed since trauma = 12.26 2 1.24 (S.E.) years. Mean time in treatment = 9.6 f 1.1 (S.E.)years. All patients were free of any cognitive impairment or psychotic symptoms and were in ongoing treatment. Data were compared to published American norms, from the U.S. National Probability Sample (Cloninger, 1994). Data were also compared to normal Israeli group (Ebstein et al., 1995) consisting of 124 normal young volunteers, not stratified or randomly selected. Statistical analyses performed using the SPSS software program. Student’s t-test (two-tailed) was used to compare T P Q in patients versus normal volunteers and the Fischer’s t-test within the study sample.

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RESULTS The comparative analysis of the data between the three populations elicited the results presented in Table 1. Harm avoidance (HA) scores were found to be significantly higher for the PTSD study sample as

Mental Health Center, Anxiety and Stress Research Unit (M.K., H.C., M.A.M., A.M., Z.K.), Department of Behavioral Sciences (M.A.M.), Ben Gurion University of the Negev, Beer-Sheva, and Souraski Medical Center and Sackler Medical School, Tel Aviv University, Tel Aviv (A.B.), Israel

Received for publication December 20, 1995; revised May 20, 1996; accepted May 30, 1996. Address reprint requests to Moshe Kotler, M.D., Beer-Sheva Mental Health Center, Anxiety and Stress Research Unit, P.O. 4600, Beer-Sheva, Israel.

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TABLE 1. Mean TPQ score in PTSD patients versus Israeli normal subjects and U.S.normsa

Temperament subscale

PTSD patients (N=46)

Novelty seeking (NS) Harm avoidance (HA) Reward dependence (RD134) Persistence (RD2)

15.7 * 5.1:,* 25.3 * 5.5 10.4 i 4.5'," 4.8 * 1.9

Normal subjects (from Ehstein et al., 1995) (N=124)

U.S. norms (from Cloninger, 1994) (N=1019)

16.2 i 4.9

13.0 i 5.0 12.0 f 5.9 13.4 * 3.4 5.5 * 1.9

12.3 * 5.8 13.7 i 3.4 4.9 * 1.9

"Resultsare expressed as mean i S.D. *p < 0.001 signifirantly differentfiom U.S. norms. "'p < 0.001 significantly dtfferent fiom Israeli normal control.

compared to the Israeli (t (123) = 23.14; p c 0.001) and American conrrol populations (t (45) = 1 S . 2 ; ~< 0.001). Novelty seekmg @IS) was also significantly higher (t (45) = 3.7; p < 0.001) for the PTSD study population compared to the American control population (t (123) = 0.96). Reward dependence (RD) was significantly lower for the PTSD study population, as compared to the Israeli (t (123) = 10.2; p < 0.001) and American control populations (t (45) = 6.0; p < 0.001). No significant differences were found between the three populations for the persistence variable. The internal analysis of the study population revealed significantly higher HA scores for unemployed patients as compared to those who were currently working (t (28) = 2.3; p = 0.03). No significant differences in T P Q scales were found for other variables including sex, education, ethnic group (Ashkenazi vs. Sephardi), age, origin of the trauma (war, car accidents, acts of terror or military vs. civilian) or time passed from the traumatic event.

DISCUSSION The results of this preliminary study show differences in certain personality dimensions of a sample of patients diagnosed as suffering from PTSD, as reflected in their TPQ scores relative to those of two control populations. The PTSD sample scored significantly higher than the control populations on harm avoidance. This is compatible with a tendency to be cautious, fearful, tense, and passive (Cloninger, 1994). HA is also elevated in depression and anxiety (Brown et al., 1992; Cloninger et al., 1993). T h e high scores of HA in our PTSD patients could be due to depression and anxiety which are common associated features of PTSD. Alternatively, high HA could be a premorbid risk factor for PTSD. Within the study sample, unemployment was associated with significantly higher HA scores. The PTSD sample also scored significantly lower than the control populations on reward dependence, which is compatible with a tendency to be socially isolated and insensitive (Cloninger, 1994). RD may be low in PTSD patients because individuals less depen-

dent on peer approval are more likely to have an avoidant and withdrawal response following the exposure to psychological trauma; individuals with higher RD might have response to psychological trauma other than PTSD. Additionally, the PTSD sample showed elevated NS scores which could suggest that novelty seeking may be a factor in attracting such individuals to expose themselves to potential traumatic situations (e.g., individuals high on NS might drive at high speeds and be more likely to get involved in car accidents). NS was also elevated in the Israeli comparison group, but NS correlates negatively with age and thus this relatively young sample may have elevated NS scores. Further prospective studies exploring heritable temperamental dimensions in PTSD may prove to be of value €or understanding the role of these variables in the individual predisposition to the psychopathological consequences of exposure to traumatic events. Acknowledgments. We thank Yemima Osher, for use of her Hebrew translation of the TPQ, and Prof. R.H. Belmaker for his valuable advice and helpful suggestions in preparing this manuscript.

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Temperamental Variables in PTSD Patients

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