Assuming that science "cannot prove anything", by what method did you come to the conclusion that "psychmeds" always destroy the brain? And why do you think this "method" is superior to science?
That's probably an overstatement, but antidepressants surely don't work as well for depression as psychiatrists make them up. However much of the overprescribing of antidepressants isn't due to psychiatrists, but due to primary physicians. Just take a look into the german guideline for major depressive disorders and you will see that antidepressants are only regarded as obligatory for severe depression, where they outperform placebo. You also need to consider that antidepressants are not only taken for mental disorders, but for some organic ones as well, for example neuropathic pain.
Are you really sure that you can regard mental illness as "psychological illness"? This term would imply that you could understand mental illness solely on the base of psychology, so you completely restrict yourself on some kind of software layer. Unfortunately things are more complex than that and there is a myriad of evidence for biological factors at play in mental disorders, even when ties to psychosocial factors are particularly strong (e. g. post-traumatic stress disorder).
Apart from that the relationship between mental illness and past experiences might be more complicated than you think and transcend psychological boundaries. For example longterm stress is known to directly destroy neurons in the hippocampus, which is a brain region involved in memory and emotional experience. Indeed people with depression and trauma-based disorders often have a smaller hippocampus than healthy people and treatments like drugs and electroconvulsive therapy have been shown to increase the volume of the hippocampus.
Unfortunately that can happen as well and often does in depersonalization disorder (about 50% of all cases).
In the family of my sister in law most suffer from depression and have been taking antidepressants for many years. To me they appear normal and not emotionally restricted or unmotivated in any way and are able to function normally for the most part. In contrast her father has been depressed probably for decades and never received treatment up to now, but heavily self-medicated with alcohol instead. Apart from liver dysfunction and painful peripheral neuropathy he got esophageal cancer out of it. It's very likely that he will die in less than half a year. Antidepressants might have prevented that.
You see, anecdotal evidence can go either way.
1. Most human beings get ill out of nowhere at some point in their lives with an illness that is incurable or even fatal. Never heard of cancer or other causes of death?
2. Just because something is "natural" that doesn't mean it is good. If we lived "naturally", i. e. as cave men, with high likelihood you would have died as a baby.
3. "Damage" does not need to be bad. In surgery we also "damage" the body in some way in order to make it work better.
However you got a point with your claim that psychiatric drugs are more on the sedating side, which turns me to why depersonalization disorder is ignored.
This is a complex question to which nobody has a definite answer. Some scholars speculated about reasons for this situation, but none of them were really convincing. In my opinion the most likely reason is that each profession and by extension every medical speciality forms some kind subculture. This subculture determines which diseases and symptoms are taken seriously and given priority and which are ignored and minimized.
For example in ophtalmology the visus and the visual field are the most important things. This leads to eye diseases being ignored, which leave both of them intact, but can severely decrease quality of life by compromising other visual functions. The classic examples are floaters, dry eyes and higher order aberrations. Patients with those diseases are routinely ignored and belittled and treatment that could work for them is denied or not easily available, while at the same time refractive surgery (e. g. LASIK) is handed down without any medical indication, although it frequently causes floaters, dry eyes and higher order aberrations. The target of ophtalmology isn't to maximize quality of life, but to maximize visus. Obviously both targets are not orthogonal, but there are many cases, where they are not in accordance.
My idea is that psychiatry is also affected by such a bias towards certain symptoms at the expense of other equally distressing symptoms. In the case of psychiatry this chasm lies between positive and negative symptoms. Positive symptoms include patients with striking and eye-catching symptoms, for example sad depressives, insane psychotics, petrified catatonics, self-injuring borderliners and skeletonized anorectics or whatever you traditionally regard as "being crazy". Consequently many treatments in psychiatry sedate people down or help them to regulate their behavior more effectively, so that at least they look normal from the outside, but often at the price of reducing their capacity for normal emotional experience.
People with negative symptoms have lost mental functions, especially in terms of affectivity, so they include people with emotional numbness and depersonalization. But these symptoms are for the most part subjective and people are already calm and look normal. That's their misfortune, because now they are outside of psychiatry's loot scheme. The idea of "insanity" in psychiatry is of people delivering a show of profound objective behavioral abnormalities, but not of an disruption of their subjective inner world. That's the bitter irony: Many people with depersonalization disorder are afraid of getting crazy, but the fact that they are not "crazy" in the traditional sense is the reason why their disorder is not taken seriously.
It isn't "science" that is at fault here much in the same way a wrench isn't at fault, when you try to repair a toaster, but it breaks apart once you turn it on. Certain cultural values inside psychiatry prevent depersonalization disorder from getting the recognition it deserves. It's human error.
I'm explaining this as cognitive dissonance (you can look this up on Wikipedia):
1. They (unconsciously) consider patients who look normal as not worthy of suffering,
2. but are told by the patients that they are suffering nonetheless.
To resolve this cognitive dissonance they are throwing off what is harder to reconcile with their beliefs. And that is point (1) by diagnosing patients with a disorder that is worthy of suffering. And that is psychosis, because depersonalization can occur as a symptom of psychosis.
Many people with depression loose their jobs, family and marriage well before they ever see a psychiatrist. Psychiatry still has a heavy stigma and usually people see a psychiatrists years after their problems started.
The problem is they never really tried.
And how are they supposed to influence these "deep biographical-personal-psychological hurt and micro traumas"? Should they build a time machine to prevent you from experiencing them?