Maladaptive learned behaviors change the physical structure of the brain.

Do you ever feel like they are just weird manifestations of the accumulations of various stressors in life? Perhaps, there is nothing /neurologically/ different -- at least not to a significant enough degree? What then?

I am not trying to be all woo-woo about this, but we live in a time where technology, and not just recent technology, has propelled us far further than we ready for?

I had trouble sitting still and learning in school, but I was able to fake it enough to learn quickly enough to make it through undiagnosed. However, I still caused various other problems i.e. class clown with good enough grades to not get in trouble. Still, I always found school to be tortuous and stressful (I still would if I had to go back).

However, I like to take a step back when things that bothered me like what I mentioned above start to creep back into my mind -- If I were born 100, 200, ... , 9900, 10000 years ago, how much disorder would I have likely faced? I wouldn't have had trouble focusing in classrooms when there were no classrooms for the below average to average person like myself. How would my life have been? Would I have been 'normal?' If so, then maybe... I'm 'normal,' now?

I cannot speak for mental disorders, but I hope my fellows can find peace. We didn't choose this system, and this system doesn't care about us, but when the sun goes down, the moon comes out. I feel like I have a duty to myself to enjoy life, normal or not, because really... It's not like anything life matters anyway.

Expensive for the patient, the hospital, or both?

In my experience, I had an fMRI a year or so ago, and it was cheaper than the psychological evaluations I had to do almost a decade ago, fwiw. But that is just my anecdote. I am sure different health care systems, different counties, etc. impact this significantly.