>However, depression is a disease independent of external factors. Citation needed. The popular theory of depression being caused purely by a "chemical imbalan

>However, depression is a disease independent of external factors. Citation needed. The popular theory of depression being caused purely by a "chemical imbalance" independent of all other factors remains unproven, though it does make for a good and simple advertising ploy for big pharma in that it makes their consumers believe the only way to happiness is through their patented drugs.