[lawl]

There are e.g. some theories that it could be an evolutionary strategy.

> Another reason depression is thought to be a pathology is that key symptoms, such as loss of interest in virtually all activities, are extremely costly to the sufferer. Biologists and economists have proposed, however, that signals with inherent costs can credibly signal information when there are conflicts of interest. In the wake of a serious negative life event, such as those that have been implicated in depression (e.g., death, divorce), "cheap" signals of need, such as crying, might not be believed when social partners have conflicts of interest.

https://en.wikipedia.org/wiki/Evolutionary_approaches_to_dep...