Last night I was chatting to a friend about depression. As someone who is still recovering from depression she kept referring to it as “her weakness” which bothered me a little. This lead to her sharing with me a perspective on depression she had encountered recently: that depression was a method by which nature would rid a tribe of weaker members. Presumably it worked something like this: a person who couldn’t meet the expectations placed on them by their tribe would develop depression and end their own life so that only the strong members would survive. Thus it is a form of eugenics programmed into our psyche to effectively off ourselves for the benefit of the rest of the tribe. Now, I am trained as a biologist and such a genetic trait is unlikely to be passed on via natural selection because it actually lowers the probability of an individual passing on their genetics. Such genes usually die out quickly. However, this got me thinking about something: if so many people have the potential to get depression – why would such a trait be preserved by natural selection? What survival advantage does a propensity for depression actually have? Here is my case on why depression is helpful rather than harmful.