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Suicide rate tied to drought

The rising suicide rate among men in rural Australia was associated with worsening drought conditions, according to study results.

The researchers said there are several plausible reasons drought may affect the suicide rate.

“First, droughts increase the financial stress on farmers and farming communities,” the researchers wrote. “Such difficulty may occur in conjunction with other economic stresses, such as rising interest rates, falling commodity prices, or an unfavorable foreign exchange rate. Second, environmental degradation can take a great psychological toll, which may be acute during droughts, linked with decisions and actions to sell or kill starving animals or to destroy orchards and vineyards.”

Such loss could place a burden on the mental health of farmers and their families, they said.

Ivan C. Hanigan, a PhD student at the National Centre for Epidemiology and Population Health at Australian National University, and colleagues analyzed nearly 4 decades of climate data from the Hutchinson Drought Index, between 1970 and 2007, comparing drought cycles with national suicide rates obtained from the Australian Bureau of Statistics. The researchers defined drought as “a persistent lack of rainfall compared with a location’s median rainfall.”

Hanigan and colleagues found an increased relative risk of suicide of 15% (95% CI, 8-22) for rural males aged 30 to 49 years when the drought index rose. However, the rural female population experienced a statistically significant decrease in suicide risk (–0.72 annually; 95% CI, –1.32 to –0.01). This finding was unanticipated, the researchers noted, given that earlier research indicated greater risk in females than males. A statistically significant increase in the relative risk associated with drought was also observed in rural males aged 10 to 29 years (P<.01).

Separate from the drought, the researchers found an increased risk associated with warmer months in spring and early summer, with the suicide rate rising approximately 3% (95% CI, 1-5) for every 1.6 °C increase per month.

The number of suicides in rural males aged 30 to 49 years due to drought represented about 9% of total deaths in that group during the study period. The researchers said greater understanding of this issue has important public health implications.

“Identifying the periods of greatest risk may allow better use of limited resources, such as promotion of counseling services to target vulnerable persons, not only during extended droughts, but also each spring. … We suggest that future suicide research should consider the causation of suicide using a holistic framework that involves financial, physical, social and human factors together with natural influences, such as season and climate change,” the researchers wrote.

Disclosure: The researchers report no relevant financial disclosures.