Suicide trends following the Taiwan earthquake of 1999: empirical evidence and policy implications

Mental health impact of severe earthquakes on survivors has attracted considerable attention. Suicide represents a terminal outcome of the spectrum of potential major mental health issues spawned by severe earthquakes. This study used time-series analysis to examine the time trends of increased suicide rates after the Chi-Chi earthquake of 1999 in Taiwan in the affected counties.

Adult cause of death data were used to study monthly suicide rates per 100,000 adult population in the study and control counties, during January 1995 to December 2001. Box and Tiao's event intervention analysis was used to examine changes in monthly suicide rates before and after the Chi-Chi earthquake.

During the post-quake period, October 1999 to December 2001, the mean monthly suicide rate in the affected counties was 1.567 per 100,000, compared with the control counties' rate of 1.297 per 100,000. Mean monthly suicide rate among the high-exposure group was 42% higher during the 26 months following the earthquake than the average for the entire observation period. Examined by time trends, the increased suicide rate registered in the first month following the quake began a monthly gradual decline by 0.7/100,000 thereafter, accounting for a total reduction of 98% in quake-related suicides by the end of 10 months. Suicide rates fell to the baseline level after 10 months.

We found that the mean monthly suicide rate for earthquake victims was higher while the low-exposure group remained stable and consistent throughout the observation period, indicating that the impact on the high-exposure group was attributable to the earthquake. This indicates the need for providing strengthened psychiatric services during the first year following major disasters.