Just like UK did decades ago before it was realised mental health issues can be diagnosed and treated.
Thailand, as a whole, is still in that era. Whether it's dementia, schizophrenia, bi polar, autism, etc. Whatever the age, people suffering with such are left in the community and expected to live a normal life, untreated.
If a crime is committed or they are deemed a nuisance to society, they will be locked up with no treatment.
Thailand needs to move forward on this. First stop is parents needing to understand and accept their kid is different to other kids and might need help.