Around 20 years ago Matthieu Ricard, Buddhist monk with a PhD. in Cellular Genetics taught us that «happiness can be trained» on YouTube:

But then four years ago Neuroscientist Rico Nil (64) who was Medical Director of Lundbeck pharmaceuticals Switzerland for 36 years started to suffer from depression from one day to another & then was treated by psychotropic (Lundbeck?) drugs:

So what should we say about all of that? Peter Gamma from www.petergamma.org says about it: avoid to watch YouTube videos as much as possible, since there might be many paid promotional videos among those which are not declared as such.