The Psychological Impact of Terrorism: An Epidemiologic Study of Posttraumatic Stress Disorder and Associated Factors in Victims of the 1995–1996 Bombings in France

The target population was made up of victims who had been directly exposed to the bombings. The French Terrorism Victim Guarantee Fund required every person applying for compensation to undergo an evaluation, carried out by independent experts, to confirm exposure to the bombing and to assess its health consequences. Participants were civilian, 18 years or older at the time of the event, spoke French, and could be reached by telephone. SOS Attentats, a nongovernmental organization created in 1986 to represent French victims of terrorism, identified the sampling frame and contacted the subjects. Of 450 subjects who applied for compensation, 222 (49.3%) chose not to undergo the French Terrorism Victim Guarantee Fund evaluation. Thus, 228 subjects remained for whom direct exposure was confirmed and who were contacted by SOS Attentats. In compliance with French law, details about the target population, data collection protocol, and procedures guaranteeing anonymity were reported to the Commission for Computer Privacy.

SOS Attentats sent an information letter to eligible participants 10 days before the study began. This was followed by a telephone invitation to participate in the study from a survey research institute. After describing the study to subjects, oral consent was obtained. Data were collected from September 16 to October 5, 1998, by computer-assisted telephone interviews conducted by 20 professional interviewers. The validity of using the telephone to assess anxiety-related stress disorders has been demonstrated in several studies (23, 24).

We defined PTSD at follow-up with a 22-item standardized instrument based on DSM-IV criteria (25–27). The structure and details of the instrument were very similar to the DSM-IV criteria—we simply broke some criteria down into several items to make them more understandable, as a back-translation confirmed. In a different, unpublished study, the reliability (Cronbach’s alpha=0.91), specificity (0.88), and sensitivity (0.73) of the instrument were confirmed in a group of 15 subjects with PTSD and 33 subjects with anxiety or depressive disorders; concurrent validity was compared with the judgment of an external clinical expert with substantial experience in the use of semistructured instruments (G. Sydor, Faculty of Psychology, Catholic University of Louvain, Belgium). Questions asked about symptoms associated with the event (e.g., “Do you currently have, without wanting them, upsetting memories about the attack?”), the duration of symptoms (more or less than 1 month), and repercussions on social and work life. Symptoms were rated on a 5-point intensity scale (0=not at all; 4=very much). A score of at least 3 defined the presence of a symptom.

Risk factors and health outcomes were also assessed by questionnaire. An initial gravity score was used to classify injury severity as mild (no hospitalization or surgery), moderate (initial hospitalization of less than 1 week or delayed/deferred surgery), or severe (initial hospitalization of more than 1 week). Perceived threat was coded as present for subjects who answered “yes” to at least one of two questions: Did you see people injured or killed during the attack? Did you feel you were dying during the attack? Hearing problems were assessed with four questions: Do you have hearing problems related to the attack? Have you seen a specialist in the past 4 weeks for a hearing problem related to the attack? Have you had buzzing or ringing in one or both ears in the past 4 weeks? Do you wear a hearing aid because of the attack? Hearing problems were coded as severe for subjects who answered yes to at least two questions and moderate for those who answered yes to one question. Four questions from the Burn-Specific Health Scale (28) were used to assess cosmetic impairment: Did the attack change your appearance to the point of interfering with your relationships? Would you like to forget that your appearance has changed? Do you feel that members of your family and friends are uncomfortable around you because of your appearance? Do you have the impression that people would not want to touch you? Questions were rated on a 5-point intensity scale (1=very much or all the time; 5=not at all or never). Cosmetic impairment was defined as a rating of 1, 2, or 3 in response to at least one of the questions. Psychiatric history was assessed with three questions. Two addressed the use of tranquilizers or sleep-inducing drugs for at least 6 months at any time before the attacks, and one addressed psychological problems: “Before the attack, had you been followed by a general practitioner, psychiatrist, psychologist or other psychotherapist for more than 6 months for a psychological problem?” A psychiatric history was defined as present if at least one of the three questions was answered positively.

Factors associated with PTSD were investigated with univariate logistic regression followed by multiple logistic regression analyses. A forward/backward stepwise procedure was used to retain explanatory variables in the models. At each step, a new variable was entered in the model, which was then recomputed to test whether this variable should remain in the model (and another be withdrawn). This process continued until no variable in the equation could be removed and no variables not already in the equation could be added. The entry and exit thresholds for other variables were p=0.15 and p=0.05, respectively; we used the Hosmer and Lemeshow goodness-of-fit test and the c-index to evaluate the fit of the resulting model. We used SAS (version 6.12) software (SAS Institute, Cary, N.C.) for all statistical analyses.

At the follow-up assessment, approximately three-quarters of the respondents (74%) were younger than 50 years old, were employed (76%), and were living with a partner (70%) (Table 1). More than half were women and had completed high school. The majority of respondents (83.7%) were injured in one of the two Paris subway bombings. The mean interval between the event and follow-up was 2.6 years (SD=0.6, range=1.8–3.2).

PTSD at the follow-up assessment was identified in 61 respondents (31.1%) (Table 2). The prevalence of PTSD in those with severe injuries was 50% (95% CI=34.1%–65.9%) and was lower in participants with moderate or mild injuries (27% [95% CI=17.5%–36.8%] and 26% [95% CI=16.2%–35.8%], respectively). The most and least frequent symptoms were reexperiencing the event (76%) and avoidance of reminders of the event and numbness of feelings (33%), respectively.

Results of univariate analyses indicated that the risk of PTSD was significantly higher for women; participants 35–54 years of age; those who were not working; those who lived alone; those whose marital situation had changed after the attack (divorce, widowed); those who had severe injuries, cosmetic impairment, or hearing problems; and those who reported a high perceived threat at the time of the attack or who had received treatment by a psychologist since the attack (Table 3). A history of psychiatric disorders was associated with a nonsignificant increase in the prevalence of PTSD. The prevalence of PTSD was not associated with the site of the attack or the number of years since the attack. Multiple logistic regression analyses showed a significant association between PTSD and age (35–54 years), sex, marital status, injury severity, cosmetic impairment, and perceived threat (Table 3). The odds ratios associated with these variables in the multiple logistic regression analysis did not substantially change from those in the univariate analysis. The Hosmer and Lemeshow goodness-of-fit test and the c-index show that the model fit the data well.