Association of rates of household handgun ownership, lifetime major depression, and serious suicidal thoughts with rates of suicide across US census regions.

OBJECTIVE: Cross sectional studies in the United States often find a significant positive association between levels of household firearm ownership and suicide rates. This study investigates whether the association can be explained by differences in levels of mental health.
METHODS: The relationship between household handgun ownership and overall suicide rates across United States regions after accounting for two mental health variables-lifetime prevalence of major depression and serious suicidal thoughts-were examined. Analyses also add another control variable (urbanization, education, unemployment, or alcohol consumption). Data on mental health variables come from the National Comorbidity Study, conducted in the early 1990s. Data on household handgun ownership come from the General Social Surveys.
RESULTS: Across the nine regions for the early 1990s (n = 9), household handgun ownership rates are positively correlated with the suicide rate (r = 0.59) and are not correlated with either the lifetime prevalence of major depression or suicidal thoughts. After controlling for major depression and suicidal thoughts (and any of the four additional control variables), handgun ownership rates remain significantly associated with the overall suicide rate.
CONCLUSIONS: In United States regions with higher levels of household handgun ownership, there are higher suicide rates. This relationship cannot be explained by differences in the prevalence of two mental health indicators-lifetime rates of either major depression or suicidal thoughts.