We need a more inclusive society for this reason. Things like bullying and other ego boosters at the cost of others separate people.
Not all mental illness is chemical, but a lot very much is.
Antidepressant drugs do work, but we don't really know why. Selective serotonin reuptake inhibitors appear to work. So do monoamine oxidase inhibitors. So do selective norepinephrine and dopamine reuptake inhibitors. We used to think that tianeptine was a serotonin reuptake enhancer, but we now think it's a mu-opioid agonist; either way, it seems to work as an antidepressant. Opipramol is a stone cold whodunnit of a drug.
Nobody really knows what causes depression. We know that there are certain risk factors, we know that there are useful treatments, but we don't really have a clue what's going on inside the brain.
The chemical imbalance hypothesis isn't particularly accurate or particularly helpful. Psychiatrists see some patients who are severely depressed for no apparent reason, but most see far more patients who just have lives that would make anyone miserable. Depression is emphatically not randomly distributed - prevalence rates are vastly higher in certain groups, for reasons that can only plausibly be psychosocial. The chemical imbalance hypothesis lets society abrogate responsibility for the fact that a lot of people are justifiably downtrodden, despondent and hopeless.
We need to recognise depression as a complex, multifaceted disorder with neurological, cognitive and social components. Antidepressant drugs have life-changing effects for some patients, but psychotherapy and lifestyle interventions are also enormously valuable. Some patients achieve complete remission within weeks of starting antidepressant drug treatment; others have tried four or five drugs with no noticeable benefit. If you're suffering from depression, you'd be foolish not to try drug treatments, but you'd be equally foolish to only try drugs.
1. We know that the symptoms of many different varieties of mental illness have been helped by the administration of SSRIs and other drugs that alter brain chemistry.
2. But what we most assuredly do not know is that mental illness patients have detectably different brain chemistry from baseline.
We assume from (1) that (2) follows, but we have no actual evidence of (2). Herein lies the problem. We cannot make a scientific statement on (2) predicated only on (1).
In this specific sense, OP is correct. And the downvotes are unfair. And more research is needed.
Not saying that depression isn’t a serious issue and that it can just be “thought away” though. But the drugs are really only helpful to some people, and there’s not much evidence to substantiate that this is just a chemical problem. There may be a chemical element, but IMO this is being exaggerated for profit. Meanwhile we aren’t dealing with any of the underlying social problems that probably play a much larger part.
I really recommend the book. If you're not convinced or just want an audio version, then I recommend the episode of the Ezra Klein Show podcast where Johann Hari is a guest - that's what convinced me to read the book.
> we aren’t dealing with any of the underlying social problems that probably play a much larger part.
I assume your concern for evidence applies to your pet theory as well, are you able to share any?