My doctor, God bless her, agrees with this. She said everyone has been pointing to Serotonin, when the real issue is Dopamine, it is Dopamine that makes us feel good. She suggests making a Dopamine list of the things that make you feel good, that are safe,not nicotine or stimulants, but the little things, getting that word correct in a crossword, petting the dog, putting on a pair of clean socks, a lot of it is sensory, some of it is addicting (getting that drop in a video game, etc.) As long as it is in moderation, it is good for you.