Persistent mental health disturbances during the 10 years after a disaster: four-wave longitudinal comparative study

Although some studies have examined the long-term effects of disasters, very little is known about severe persistent symptoms following disasters. The aim of the present study was to examine persistent mental health problems and to what extent disaster exposure predicts long-term persistent disturbances.

Following a major disaster, a four-wave study was conducted (surveys 2-3 weeks, 18 months, 4 years and 10 years after the event) that examined severe post-traumatic stress disorder (PTSD) symptomatology (Impact of Event Scale), anxiety and depression symptoms and sleeping problems (Symptom Check List-90-R), and use of physician-prescribed tranquilizers. Participants were affected adult Dutch native residents (n = 1083). At wave 2 and 3, a control group participated (n = 694). At wave 1, severity of disaster exposure was examined. Multiple imputation was used to target the problem of missing data across surveys due to non-response such as in the fourth wave (61%).

In total, 6.7% (95% confidence interval [CI]: 5.1-8.2) developed persistent PTSD symptoms during the 10 years after the event. For anxiety, depression, sleeping problems these prevalences were 3.8% (95%CI: 2.7-5.0), 6.2% (95%CI: 4.7-7.6) and 4.8% (95%CI: 3.5-6.1) respectively. In total 1.3% (95%CI: 0.6-2.0) used tranquilizers at all waves. Approximately one out of 10 with severe symptoms 2-3 weeks after the event, developed persistent symptoms. Even in the long term, affected residents compared to controls had more often chronic anxiety symptoms and sleeping problems. High disaster exposure independently predicted persistent PTSD symptoms (adjusted odds ratio [adj. OR], 4.20; 95%CI: 2.02-8.74, P < 0.001), anxiety (adj. OR, 3.43; 95%CI: 1.28-9.20, P < 0.01), depression symptoms (adj. OR, 2.95; 95%CI: 1.26-6.93, P < 0.01), and sleeping problems (adj. OR, 3.74; 95%CI: 1.56-8.95, P < 0.001).

Post-disaster mental health care should (also) target persistent mental health disturbances in the long term, especially PTSD, anxiety, depression symptoms, and sleeping problems. High disaster exposure may be an early marker for risk of persistent symptoms.