The association of adverse mental health effects with repeated exposure to disasters.

BACKGROUND: It has been assumed that the mental health effects of repeated trauma should be incrementally greater than simple additive effects of separate trauma. However, repeated disasters afflicting the same population are uncommon. This study investigated psychiatric disorders following differential exposures to repeated disasters.

METHODS: Mental health effects of exposure to repeated disasters of 547 individuals exposed to either flooding, tornadoes, dioxin contamination, and/or radioactive well water were assessed. Structured diagnostic interviews assessed prevalence of psychiatric disorders before and after each of the disasters. A multiple logistic regression model was used to test the association of post-disaster disorders after each flood with the total number of flood exposures, controlling for lifetime pre-disaster disorders.

RESULTS: Approximately one-fifth to one-third of the disaster-exposed groups had a psychiatric disorder following exposure to disaster, but disaster-related posttraumatic stress disorder and incident psychiatric disorders were nonexistent or rare in both post-disaster periods. Most identified post-disaster psychopathology consisted of alcohol use that predated the disasters.

CONCLUSIONS: Findings suggest that alcohol use disorder may be more representative of a risk factor for, rather than an outcome of, flood exposure. This possibility is supported by the high lifetime pre-flood prevalence of alcohol use disorders in flood plain populations.