Pre-disaster PTSD as a moderator of the relationship between natural disaster and suicidal ideation over time

Natural disasters are associated with a variety of negative health consequences, including enhanced suicide risk. Factors that moderate the relationship between disaster exposure and enhanced suicide risk are unknown. The aim of the current study was to determine whether pre-disaster PTSD moderates the association between change over time in thoughts of death, suicidal ideation (SI), suicide plans, and suicide attempts (SA) from pre- to post-disaster.

Participants (n = 2832) were recruited from Chile as part of the larger PREDICT study and completed a measure of lifetime PTSD and panic disorder at baseline and a lifetime death/suicide measure at baseline in 2003 and again 6, 12, and 24 months later (i.e. "pre-disaster"). One year following a major earthquake and tsunami in 2010 (i.e., "post-disaster"), participants completed another death/suicide measure.

Both those with and without pre-disaster PTSD experienced significant increases in SI from pre- to post-disaster. However, pre-disaster PTSD was associated with significantly accelerated increases in thoughts of death and SI from pre-to post-disaster. At nearly all time-points, pre-disaster PTSD was associated with higher thoughts of death and SI, suicide planning, and SA. In contrast, panic disorder did not moderate the association between time and changes in SI.

There was a long time-gap between pre-disaster and post-disaster, with limited data about what occurred during this time.

Pre-disaster PTSD is an important predictor of increased SI following a natural disaster, and groups with pre-disaster PTSD should be prioritized for receipt of mental health resources following a natural disaster.