There are many types of depression, or causes, both biochemically and psychologically.
For example for women with severe PMS and/or post partum there is a copper toxicity depression that only happens when certain hormones are out of balance.
This is why genotyping is such a fabulous medical screening diagnostic tool as it determines which type of depression a person is more likely to have and which treatment and dose would most likely be best/ This all from looking at DNA.
My working theory is that each person is chemically unique, that each body is hard-wired to heal.
The problem is that 9 out of 10 people are slow-poisoning themselves, ignorant of the effects until expression of a more serious condition, usually in the form of a physician’s ignorant “diagnosis” and assigning a label to the condition with a corresponding chemical treatment (pharmacological).
Modern medicine - absent surgical procedures and genetics, with few other exceptions - is a joke, literally almost stuck in the dark ages. I’d go see a Chinese herbalist before an MD...