They've grossly let down everyone, but since there's a higher proportion of people with autism that suffer from depression and anxiety which they often separately diagnose as "mental illness" and also because sometimes they even call ASD a "mental illness" (IT'S DEFINITELY NOT), they've let down a higher proportion of autistic people compared to the general population. It's not just mental health "professionals" (and I use the term "professionals" very loosely) that have let everyone down, it's also the very powerful and corrupt pharmaceutical companies that push harmful and addictive mind altering drugs that the so called "professionals" can then use as a cheap "quick fix" in an often underfunded system where real treatment isn't seen as feasibly possible for most people that truly need it. The problem is these drugs are a vicious circle because they often make people worse in the long term which puts a constant strain on resources. Even heroin is a "quick fix" for depression, it's great in the short term because it most definitely takes all your worries and anxiety away, but most of us know that the negative effects greatly outweigh the short term positive, with prescribed drugs it's just not as obvious and blatant.
Mental health institutions have also massively failed where they became a place of extreme abuse and punishment to people who were often supposed to be "patients", not prisoners. I believe many of these institutions were closed and knocked down in recent years to cover up and forget about the shocking abuse that went on since much of it was being uncovered. There are still however a reduced number of institutions even today and from the testimonies of an ex patient I know that spent a short time in one only a few years ago in the UK, shocking abuse is still rife and their main treatment is to forcibly drug "patients" up as much as possible to make them easier to manage. These horrid institutions only serve to make people much worse, not improve their recovery.
In my opinion they have also often used mental health patients to test and experiment with "treatments" over the years that are often very dangerous and detrimental, here's a couple of examples:
Electroshock therapy
Many people believe that this totally barbaric "treatment" was only used many years ago, but they'd be surprised to learn that it's still often used even today, except due to the very negative publicity the name has been changed to
electroconvulsive therapy or ECT. The link worryingly takes you to an article on the official website of the largest and most respected mental health charity in the UK called
Mind, their article shows the "treatment" in a positive way, but please don't be fooled, it's very dangerous, barbaric and often very detrimental. For instance there's been many cases where people have permanently lost memory (apparently a third of patients report memory loss, please
click here for more). I saw a documentary on TV a long time ago where one such person had apparently "awoke" as a new born baby in an adult's body, he had to be bought up through childhood all over again and taught everything, he never regained his former life memory and who knows perhaps he was even a completely different conscious being?
Lobotomy
Lobotomy is a "surgical operation" involving incision into the prefrontal lobe of the brain (yes, they slice the actual brain itself), many articles state that the procedure was formerly used to treat mental illness and that it's totally condemned today, but this incredibly barbaric procedure which effectively causes very serious permanent brain damage was actually still performed only 30-40 years ago and there's even evidence that suggests it's still occasionally performed even today! Many lobotomy patients suffered severe negative effects to their personality and ability to function independently as well as other serious complications, in fact the transformation has even been described as changing "an insane person" into "an idiot".
They have also tested and prescribed numerous drugs on mental health patients throughout history including some drugs that are now classed as dangerous illegal street drugs.