A recent study has shown that living in high altitudes has made people 30% more likely to commit suicide. Renshaw, the leading researcher, believes one of the reasons for this is lack of oxygen. As oxygen decreases so do levels of serotonin and affect the uptake of dopamine. These are two neurotransmitters that relay signals between neurons and other cells. This in turn increases the likelihood of becoming suicidal. People can adapt to high-altitude living but women in particular are more sensitive due to a lower supply of serotonin. Those that have a pre-disposition to depression or anxiety are more likely to develop suicide tendency as well.