Suicide at High Altitude: The Importance of Sociodemographic and Mental Health Care Factors

We read with interest the recent report by Gamboa and colleagues (2011) on the possible link between depression and suicide rates at high altitude. In their reply, Brenner and colleagues (2011) wrote that, in our recent work (2011), we “reported a higher incidence of depression with increasing altitude which supports other recent findings.” While we appreciate this attention to our work, we feel we must clarify that our study did not show an increased incidence of depression with increasing altitude.

In our study, we examined 8871 completed suicides as recorded in the National Violent Death Reporting System and found that suicide decedents who had been residents at high altitudes were more likely to have family or friends report a depressed mood preceding the suicide, compared to low altitude suicide decedents. However, the database we used does not include any information about the general population, so we cannot draw any conclusions about the incidence of depression in these areas. We can only say that, for some reason, more suicide decedents at high altitude than at low altitude appeared to have been depressed at the time of their death.

It could be that this is due to an increased prevalence of depression in the general population at high altitude. However, in our study, we also found that suicide decedents at high altitude were not more likely to be in mental health care at the time of their death, despite being more likely to have appeared depressed. This suggests that there are barriers to mental health care in high altitude regions, either at the individual level (eg, hesitancy to seek help) or at the community level (eg, number of mental health workers). We also found that high and low altitude decedents differed with respect to race, ethnicity, rural residence, intoxication, firearm use, and recent financial, job, legal, or interpersonal problems; marked differences persisted after multivariate adjustment.

Our study, like the other studies that preceded it and will follow it, cannot conclusively explain the reason for increased suicide rates at high altitude. We do not dispute that hypoxia and other physiologic effects of altitude may influence an individual's mental health. However, we do feel that those interested in suicide prevention should also turn their attention other sociodemographic and mental health factors, such as the relative availability and utilization of mental health resources in high altitude communities.