If it is ADHD, OCD etc then no thinking or acting in anyway will not remove the symptoms.These are neurodevelopmental disorders, present from birth and has all kinds of genetic and structural differences in the brain compared to those without.
The brain is an organ, well comprised of many organs ostensibly, it can get sick.
I have OCD and it's nothing I can stop , think out of etc. When it is bad i can't think my own thoughts, just constant intrusive thoughts that interrupt my normal thinking. I could be reading a book and if it's bad I will think about a pain in my back maybe 100 times, I am not concerned about my back logical, it's illogical, the key part of OCD. It has waxed and waned but will never go away, it's a disease, it runs in my family. As a child I would be in existential crisis after crisis, the thoughts are absurd also in there severity. I "know" they are not my thoughts, yet when they hit it feels like everyone I know has died, there is a physical reaction, I can ignore it, move to something else but there is an uneasy dread as if nothing is right.
As a kid I would do an hourly routine at night to ensure everyone is safe. Check the taps, the cats, the fridge, the stove etc. Sometimes when it was really bad (like 12-15) I would stand over the stove with tears running down my face trying to stop touching the stove but I was stuck, checking it, looking away, feeling for heat, twisting the gauges, for over an hour. The other cruel thing about OCD is it correlates with a very high declarative memory and IQ, which only worsens things, scenarios that are so divergent they are ludicrous and completely foreign to me.
Other issues are the intrusive thoughts, for example if I was about to cross the street, my brain would give me the image of a bus hitting and killing me, it just pops in your head and it's vivid and real, as real as your own thoughts. Or knife on the counter would give me the image of stabbing my mother to death, the thoughts are always distressing and conflict with my core values.