Abstract
We appreciate reading the perspectives of Kious et al. and agree that there is an association between suicide rates and altitude of residence. However, after reviewing the published studies by Kious et al. and Renshaw et al., the questions remain the same: What is the mechanism of this association? Is the association causal? Does it persist after properly controlling for confounding personal, societal, and environmental variables? And is the magnitude of the association large enough to warrant action? Our major difference with Kious' interpretation is whether hypoxia plays a significant causal role. We have previously explored several of the articles cited by Kious and have shown that many have significant flaws despite the use of different methodologies (Reno et al., 2018).
The fundamental question is whether a mild degree of hypoxia can change physiological and cellular mechanisms to cause depression, anxiety, and cognitive dysfunction that can predispose to suicidal behavior. We are not aware of any human studies that show that a mild degree of hypoxia as found at moderate altitudes (1515–3030 m) predisposes to suicidal thoughts or behaviors. Further research into the bioenergetics of brain function may help to answer that question.
Lastly, we worry that the focus on cellular hypoxia as a cause of suicidal behavior may divert our attention from the underlying illnesses that lead to suicide, the need for mental health care and critical and proven preventative interventions. We worry that vulnerable individuals may turn to supplemental oxygen to manage life-threatening depression, as suggested in some lay press articles. We worry that patients and communities will consider oxygen as a quick remedy, rather than focusing on suicide awareness, substance use treatment programs, safe firearm storage, and expanded access to mental health care for all who need it. This would be a tragic outcome.