Depression isn't sadness. Sadness is healthy, depression is when it runs amok like a cancer, sometimes with no apparent cause. Someone with a great life, job, f

Depression isn't sadness. Sadness is healthy, depression is when it runs amok like a cancer, sometimes with no apparent cause. Someone with a great life, job, friends, health, can be horribly depressed. That's what makes it illness. It's not due to low serotonin levels. The serotonin / chemical imbalance theory has been out of favor for the past ten years: https://link.springer.com/article/10.1007/s12115-007-9047-3 https://link.springer.com/article/10.1007/s12115-007-9047-3, right now we think it's more related to decreased levels of neurogenesis but we're not entirely sure. The "happiness is an inside job" thing works if you're not depressed. When you are, it's like your "happiness muscles" don't work at all. You're just a non-responder to positive stimuli. It's like telling someone that any other illness is really their fault, with the underlying message being that they want you to go away.