HLTH 6740 Week 4 Distress Trajectory Analysis Example

Reading Distress as Movement: A Trajectory Analysis of Post-Disaster Outcomes From the First Month to the Years After

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Walden University

HLTH 6740: Disaster, Crisis, and Trauma

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Month Day, Year

Reading Distress as Movement: A Trajectory Analysis of Post-Disaster Outcomes From the First Month to the Years After

Why Trajectories

Most studies of disaster survivors measure distress once. A single measurement can show how many people are distressed at that moment but not where they are heading: whether a distressed person will recover, stay distressed or whether someone doing well now will struggle later. Trajectory research follows the same people over time and asks what patterns their outcomes follow. This paper reads the published follow-up research as movement rather than as a snapshot and draws out what it means for when and how support should be offered.

The Patterns Identified

Using two population-based longitudinal datasets, one collected after the 1999 floods in Mexico and one after the September 11 attacks in New York, Norris and colleagues tested whether six possible trajectories appeared (Norris et al., 2009). Four appeared in both samples: resistance, meaning no or mild symptoms that stayed stable; resilience, meaning moderate or severe symptoms early followed by a sharp decrease; recovery, meaning moderate or severe symptoms followed by a gradual decrease; and chronic dysfunction, meaning moderate or severe symptoms that stayed stable. Notably, neither sample showed a relapsing and remitting pattern, and only New York showed a delayed dysfunction pattern, in which symptoms appeared or worsened later.

Broader reviews reach a compatible conclusion: the most common response to disaster is relatively stable functioning, with a minority following chronic or delayed courses (Bonanno et al., 2010).

What the First Month Can and Cannot Tell

The trajectories show why the first month is a poor guide when used on its own. People on the resilience and recovery trajectories look the same as people on the chronic trajectory early on: all have moderate or severe symptoms. Only later measurements separate those who improve sharply, those who improve gradually and those who do not improve. Conversely, people on a delayed trajectory look fine early and would be missed. An early screening that sent everyone with high symptoms to treatment would treat many who would have recovered on their own, while missing those whose problems emerge later.

When Outcomes Worsen Over Time

Not every population follows the usual pattern of decline. In a representative panel of residents of areas affected by Hurricane Katrina, interviewed five to eight months after the storm and again a year later, estimated PTSD prevalence rose from 14.9% to 20.9%, and serious mental illness and suicidal ideation also rose (Kessler et al., 2008). The authors noted that this ran contrary to most disaster studies and found that unresolved hurricane-related stresses, such as ongoing housing and financial problems, accounted for large proportions of the increases. Read as movement, this finding suggests that trajectories are not fixed properties of individuals but respond to what happens to people after the event. It also cautions against reading any early improvement in a population as permanent while recovery is still unfinished.

What Shapes Which Trajectory People Follow

Reviews of risk factors help explain who follows which path. The 2002 review found that adult outcomes were worse, most consistently, with heavier exposure, with stressors that piled up after the event, with a history of psychiatric problems and with social support that was thin or eroding, and also among women, middle-aged adults and members of ethnic minority groups (Norris et al., 2002). Several of these, especially secondary stressors and deteriorating resources, unfold after the event, which is consistent with the Katrina finding that ongoing stress pushed outcomes upward. Resources lost in recovery, such as housing, income and social networks, may therefore shape trajectories as much as the event itself.

Two Composite Survivors on Different Paths

Consider two composite survivors of the same flood, interviewed one month after the event with the same screening scale. Both report frequent intrusive memories, poor sleep and avoidance of the river, and both score above the threshold for probable PTSD. The first, a homeowner with flood insurance and family nearby, returns to a repaired house within three months; by six months her symptoms have faded, which places her on the resilience or recovery trajectory. The second, a renter whose building was condemned, moves three times in six months, loses hours at work and drifts away from her church. At six months her symptoms are unchanged, and at a year they are worse.

A program that screened both at one month would have counted two cases of probable PTSD. A program that screened again at six months would have seen that only one needed treatment, and that what had changed for the second was not the flood but everything after it. The composite cases are illustrative, but they follow the patterns the longitudinal research describes.

Implications for Support

Three implications follow. First, early support should be broadly available but light, aimed at safety, calm, connection and practical help, rather than intensive treatment for everyone with early symptoms, since many will recover on their own. Second, follow-up screening months later is needed to find people on chronic or delayed trajectories, who are the ones most likely to benefit from treatment. Third, reducing secondary stressors, such as housing instability and financial strain, may change trajectories, so practical recovery assistance is part of mental health support, not separate from it.

Limits of Trajectory Research

Trajectory studies have their own limits. They require large samples followed over time, which are rare in disaster research, and the patterns found depend on the statistical methods used and the number of measurements. The two datasets above covered specific events and settings. And even the best trajectory research describes groups; it cannot yet predict with confidence which trajectory a particular person will follow. Those limits argue for measuring repeatedly rather than predicting once. For a program planner, that means budgeting for follow-up contact at several points in the first year, not only for a burst of services in the first weeks, and treating the second and third contacts as the ones most likely to find people who need more help.

References

Bonanno, G. A., Brewin, C. R., Kaniasty, K., & La Greca, A. M. (2010). Weighing the costs of disaster: Consequences, risks, and resilience in individuals, families, and communities. Psychological Science in the Public Interest, 11(1), 1-49. https://doi.org/10.1177/1529100610387086

Kessler, R. C., Galea, S., Gruber, M. J., Sampson, N. A., Ursano, R. J., & Wessely, S. (2008). Trends in mental illness and suicidality after Hurricane Katrina. Molecular Psychiatry, 13(4), 374-384. https://doi.org/10.1038/sj.mp.4002119

Norris, F. H., Friedman, M. J., Watson, P. J., Byrne, C. M., Diaz, E., & Kaniasty, K. (2002). 60,000 disaster victims speak: Part I. An empirical review of the empirical literature, 1981-2001. Psychiatry, 65(3), 207-239. https://doi.org/10.1521/psyc.65.3.207.20173

Norris, F. H., Tracy, M., & Galea, S. (2009). Looking for resilience: Understanding the longitudinal trajectories of responses to stress. Social Science and Medicine, 68(12), 2190-2198. https://doi.org/10.1016/j.socscimed.2009.03.043