Stability of Posttraumatic Stress Reaction Factors and Their Relation to General Mental Health Problems in Children: A Longitudinal Study

Abstract

The aim of this study was to evaluate the structure of posttraumatic stress reaction factors and their relation to general mental health problems in Norwegian children exposed to the tsunami on December 26, 2004. A total of 133 children and adolescents (ages 6–17) were interviewed 10 months posttsunami using the UCLA PTSD Reaction Index, and 104 were interviewed again 2.5 years after the tsunami. Confirmatory factor analyses supported the theory of a four-factor model of intrusion, active avoidance, numbing, and arousal as a better division of symptoms than the three-factor model used in the present diagnostic criteria. The factors of intrusion and active avoidance were highly correlated 2.5 years posttsunami. This association may be due to nonspecificity in these trauma-related factors as posttraumatic stress reaction levels diminish over time. General mental health problems were highly related to arousal at both assessments, supporting the theory that some symptoms of posttraumatic stress reactions overlap with other, concurrent mental problems.

Acknowledgments

We thank Øyvind Langsrud, PhD, and Tore Wentzel Larsen, MSc, for help with the statistical analyses.

Notes

Note: Exposure was reported by the parents in the questionnaire 6 to 8 months posttsunami. Immediate subjective distress was reported by the children at T₁. Posttraumatic stress reactions were measured by the total scores from children's reports on the University of California, Los Angeles PTSD Reaction Index at T₁ and T₂. General mental health problems category reflects the adolescents’ answers to the Strength and Difficulty Questionnaire at T₁ and T₂.

^a N = 133.

^b N = 104.

Note: DSM–IV–TR = Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.); PTSD–RI = University of California, Los Angeles PTSD Reaction Index; AA = active avoidance; AR = arousal; AV = avoidance; I = intrusion; N = numbing.

Note: All factors were intercorrelated in all models. Chi-square was significant, with p ≤ .001 for all models, indicating that the models did not fit the population perfectly. The factor covariance matrices were not positively definite for the four-factor numbing model at T₁ and T₂ or for the combined models across both assessments. Bold represents the models with the best fit indices. CFI = comparative fit index; TLI = Tucker-Lewis index; RMSE = root mean square error of approximation; AIC = Akaike information criterion; ML discrepancy = bootstrapped maximum likelihood discrepancy.

^a Fit indices that do not account for non-normality.

^b Compares a model's chi-square with the chi-square of the four-factor model from same data set.

^c Fit indices that account for non-normality. ML is the discrepancy between implied and population estimates. The bootstrap analyses were based on 2,000 bootstrap samples when separately analyzing models at each assessment and on 200 bootstrap samples when analyzing items from both assessments in the same model.

^d N = 133.

^e N = 104.

^f The correlation between intrusion and active avoidance at T₂ was not possible to calculate because the factor covariance matrix was not positively definite. Correlations between intrusion and active avoidance were .82 and .95 at T₁ and T₂, respectively, when defining the item “I have trouble remembering important parts of what happened” (C3) as part of active avoidance instead of numbing.

^g Confirmatory factor analyses of similarity over time, analyzing 34 items (17 items from each assessment). The 34 items were divided into eight factors (four factors from each interview). Similar questions across time could have intercorrelated error terms. Factor loadings were unconstrained in the first analyses. In the second analyses, factor loadings were constrained to be equal at T₁ and T₂. In the third analysis, factor covariance was also constrained to be equal across time.

*p ≤ .05. ***p ≤ .001.

Note: Dependent variables were mean scores (possible range = 0–4) within the four factors of posttraumatic stress reactions at the two assessments. Independent variables, exposure, immediate subjective distress, and general mental health problems were standardized before being simultaneously entered. Time and these independent variables were entered as fixed effects, whereas there were random effects for the family and individual levels. The figures in this table are estimates of nonstandardized regression coefficients (B) (SE in parentheses) of the predictors. I = intrusion; AA = active avoidance; N = numbing; Ar = arousal.

^a General mental health problems was based on the children's reports at T₁ (n = 95) or at T₂ (after slash) (n = 85).

*p ≤ .05. **p ≤ .01. ***p ≤ .001.