Really good article in the Guardian on depression:
https://www.theguardian.com/society/2018/jan/07/is-everything-you-think-you-know-about-depression-wrong-johann-hari-lost-connections
Via @anarchismhub
Reminds me of the similar discovery about drug abuse from rat park:
http://www.stuartmcmillen.com/comic/rat-park/
We need (amongst other things) purpose and agency in our lives, when we lack this we become unhappy, this may lead to depression and/or drug abuse.