Trajectories of Posttraumatic Stress in Youths After Natural Disasters

IMPORTANCE Disaster exposure is associated with the development of posttraumatic stress (PTS) symptoms in youths. However, little is known about how to predict which youths will develop chronic PTS symptoms after disaster exposure. OBJECTIVE To evaluate PTS symptom trajectories among youths after 4 major US hurricanes and assess factors associated with those trajectories. DESIGN, SETTING, AND PARTICIPANTS This cohort study used integrative data analysis to combine data from 4 studies of youths’ responses to natural disasters (hurricanes Andrew [1992], Charley [2004], Ike [2005], and Katrina [2008]) at time points ranging from 3 to 26 months after the disasters. Those studies recruited and surveyed youths aged 6 to 16 years at schools via convenience sampling of schools near the path of destruction for each hurricane. This study was conducted from August 2017 to August 2020, and pooled data were analyzed from February 2019 to October 2020. EXPOSURE Experience of a natural disaster during the ages of 6 to 16 years. MAIN OUTCOMES AND MEASURES Posttraumatic stress symptoms were assessed using the University of California, Los Angeles, Posttraumatic Stress Disorder Reaction Index (UCLA PTSD-RI) and the UCLA PTSD-RI-Revised. Latent class growth analyses were used to evaluate the youths’ PTS symptom trajectories and associated factors. RESULTS Among 1707 youths included in the study, the mean (SD) age was 9.61 (1.60) years, 922 (54%) were female, and 785 (46%) self-identified as White non-Hispanic. Four PTS symptom trajectories were identified: chronic (171 participants [10%]), recovery (393 [23%]), moderate-stable (563 [33%]), and low-decreasing (580 [34%]). Older youths were less likely to be in the chronic group; compared with the chronic group, each 1-year increase in age was associated with increased odds of being in the other groups (recovery: odds ratio [OR], 1.78 [95% CI, 1.29-2.48]; moderate-stable: OR, 1.94 [95% CI, 1.43-2.62]; and low-decreasing: OR, 2.71 [95% CI, 1.99-3.71]). Compared with males, females had higher odds of being in the chronic group than in any other group (recovery group: OR, 0.48 [95% CI, 0.26-0.91]; moderate-stable group: OR, 0.37 [95% CI, 0.21-0.64]; and low-decreasing group: OR, 0.25 [95% CI, 0.14-0.44]). CONCLUSIONS AND RELEVANCE In this cohort study, few youths reported chronic distress, and trajectories among most youths reflected recovery or low-decreasing PTS symptoms. Older age and identification as male were factors associated with decreased odds of a chronic trajectory. Youths with chronic or moderate-stable trajectories may benefit from intervention. JAMA Network Open. 2021;4(2):e2036682. doi:10.1001/jamanetworkopen.2020.36682 Key Points Question What are the trajectories of posttraumatic stress (PTS) symptoms among youths after natural disasters, and what factors are associated with those trajectories? Findings This cohort study of 1707 US youths exposed to major hurricanes identified 4 PTS symptom trajectories: chronic (10%), recovery (23%), moderate-stable (33%), and low-decreasing (34%). Female and younger youths experienced more severe PTS symptom trajectories. Meaning The findings suggest that a substantial number of youths may experience chronic or moderate-stable PTS symptom trajectories after a natural disaster and might benefit from intervention. Author affiliations and article information are listed at the end of this article. Open Access. This is an open access article distributed under the terms of the CC-BY License. JAMA Network Open. 2021;4(2):e2036682. doi:10.1001/jamanetworkopen.2020.36682 (Reprinted) February 15, 2021 1/11 Downloaded From: https://jamanetwork.com/ by a Non-Human Traffic (NHT) User on 09/17/2021


Introduction
Natural disasters are associated with the mental health of children. Approximately 100 million youths globally are exposed to disasters each year. 1,2 After disasters, primary presenting psychological symptoms among youths are posttraumatic stress (PTS) symptoms. [3][4][5] Elevated rates of PTS symptoms among youths are as high as 72% during the first 3 months after a disaster. 6 In the long term, PTS symptoms among youths are associated with poorer mental and physical health, academic performance, and vocational outcomes. [7][8][9][10][11] Thus, it is important to understand and address postdisaster PTS symptoms among youths.
Stepped care models are current best practice in addressing youths' postdisaster PTS symptoms. 12,13 Stepped care models triage youths based on assessments of PTS symptoms and other forms of psychological distress. After assessment, only youths at highest risk for chronic distress after a disaster should receive the most intensive interventions, whereas those at lowest risk receive supportive care. This stepped care approach is necessary because of the large number of youths affected by disasters alongside the limited funding available for mental health and social services after disasters. 14,15 However, a barrier to implementing postdisaster stepped care models is a lack of clarity regarding how to triage youths based on risk for persistent PTS symptoms. This barrier exists because it is unclear how youths' initial PTS symptom presentations after disasters are associated with their long-term PTS symptoms. Few studies have assessed youths at multiple time points after a disaster, and even fewer studies have assessed them beyond the first year after a disaster. 16,17 In addition, researchers have primarily assumed that all youths in disaster-affected areas follow a similar pattern of response to a disaster. However, abundant evidence from the literature on adults 18,19 and emerging evidence from the literature on children 20,21 indicates that people have different long-term patterns, or trajectories, of psychological responses to traumatic events such as disasters.
Among adults, robust evidence exists for 4 prototypical trajectories of PTS symptoms after a disaster. 22,23 Across studies, these trajectories are typically labeled chronic, characterized by high levels of persistent PTS symptoms that do not remit over time; recovery, characterized by initially elevated PTS symptoms followed by a decrease in symptoms over time; resilient, characterized by low levels of PTS symptoms over time; and delayed, characterized by elevated levels of PTS symptoms that emerge more than 6 months after the disaster event. However, adult research provides only limited insight into youths' postdisaster responses because the experiences of youths before and after a disaster are distinct from those of adults. [24][25][26] Researchers have begun to examine youths' PTS symptom trajectories following traumatic events, but findings are inconsistent. 27-29 Therefore, it is unclear what typical PTS symptom trajectories occur among youths after disasters. Studies on youths' PTS symptom trajectories differ with regard to the trajectories identified and the proportion of youths in each trajectory. [27][28][29] Variability in existing studies on youths' PTS symptom trajectories makes it difficult to interpret, compare, and resolve discrepant findings. Discrepant findings may be associated with differences in the disaster event examined, assessment timing, the analysis type, sample recruitment, or risk factors examined.
One way to provide more robust information on prototypical trajectories of PTS symptoms among youths exposed to disasters is to use integrative data analysis, which allows researchers to combine participant information from individual data sets into 1 large data set by statistically harmonizing data so that all data may be analyzed jointly. Integrative data analysis allows researchers to apply consistent analyses (eg, latent class growth analysis) to the data to obtain more robust estimates of PTS symptom trajectories and the proportion of youths experiencing each PTS symptom trajectory type.
With use of integrative data analysis and latent class growth analysis, this study pooled data from studies of 4 of the most destructive hurricanes in US history: hurricanes Andrew, Charley, Ike, and Katrina. Hurricanes are important to study because the frequency and intensity of severe storms

Measures PTS Symptoms
Symptoms Data collected for Hurricane Andrew used the older, 20-question version of the UCLA PTSD-RI. 38 Participants were asked to respond to items such as "I have arguments or physical fights"  and "I am afraid that the hurricane will happen again." Total possible scores ranged from 0 to 80, with higher scores indicating higher levels of distress symptoms. 38  A truncated summary score, ranging from 0 to 40, was created for the purposes of the integrated data analysis and contained the 10 items common to both versions of the UCLA PTSD-RI.

Factors Associated With Trajectories
The participants' demographic characteristics (ie, age, gender, and race/ethnicity) were self-reported The prevalence of clinically relevant PTS symptoms (ie, defined as meeting the severe or very severe PTS symptom score cutoffs) among youths in this study ranged from 35.7% at 3 months after a disaster to 9.8% at 26 months after a disaster (Table 1). Figure 1 shows the distribution of baseline PTS symptoms for each disaster study.
Fit indices for trajectory results are presented in Table 2. When comparing the 4-and 5-trajectory models, the proportion of the sample in 3 of the trajectories remained stable, suggesting that the 5-trajectory model was parsing the remaining trajectory into 2. Evaluating fit, theory, and existing evidence, we chose the 4-trajectory model as the final model (Figure 2   Exploratory analyses suggested that higher levels of exposure to disaster were associated with greater odds of membership in the low-decreasing and recovery trajectory groups compared with the moderate-stable group. A 1-unit increase in the exposure variable was associated with an increase by a factor of 1.59 in the odds of membership in the low-decreasing trajectory group (OR, 1.59; 95% Abbreviations: AIC, Akaike information criterion; BIC, bayesian information criterion; LMR-LRT, Lo-Mendell-Rubin adjusted likelihood ratio test; NA, not applicable in singlegroup models.  A small proportion of youths (10%) in this study reported a high number of chronic symptoms initially and that increased over time. This finding is consistent with studies of trauma-exposed adults, in which 10.6% of adults across studies exhibited chronic symptoms. 18 This finding is also consistent with a recent study of 346 children (grades 4-6) followed up for 4 years after an enhanced Fujita scale (EF)-4 tornado, in which 7% of the children exhibited a chronic trajectory. 28

JAMA Network Open | Psychiatry
In addition to the results that 23% of youths fit a recovery trajectory, this study's findings suggest that about one-third of youths who report initially high levels of distress may develop chronic symptoms. Initial efforts to triage disaster-exposed youths based on increased PTS symptoms may identify youths who will continue to report chronic symptoms and those who will recover. Therefore,

Limitations
This study has limitations. All the studies included were posthurricane studies. Findings may not generalize to other types of disaster events (eg, earthquakes or terrorist attacks). In addition, race/ ethnicity was measured as a dichotomous variable. Additional research is needed with more diverse cohorts. We also used latent-class linear growth analysis to identify trajectories. Although this is a robust analytic approach, any single analysis approach should be interpreted with caution. Future studies examining quadratic and cubic trends are needed. 50 In addition, a limited number of factors were examined in this study. We were not able to examine disaster exposure from each disaster given the timing of exposure assessments. Exposure is an important factor to consider in understanding resilience. 33,51,52 Future pooled studies should incorporate additional factors such as high anxiety, low social support, poor regulation of emotions, life stress, 20 and co-occurring depression. 39 Future pooled analyses could be facilitated through agreement on common assessments of PTS symptoms, measurement of functional impairment, and commitment to sharing data in repositories.

Conclusions
In this cohort study, few youths reported chronic distress, and trajectories among most youths reflected recovery or low-decreasing PTS symptoms. Older age and male gender were factors associated with decreased odds of a chronic trajectory. These findings may guide policy makers to effectively implement stepped care models for youths after a disaster. The results also highlight the need for health surveillance systems after disasters because many youths in this study reported elevated PTS symptoms.