True but I do genuinely believe that our thoughts and actions are not the same normally. Most people have thoughts they won't act on. If a mental illness prevents you from properly filtering your thoughts, you may act on things you normally wouldn't.

To add to this, I also genuinely believe that anyone older than like 30 has had their cognitive functions detrimentally impacted by poisons like lead gasoline, lead pipes, asbestos, etc... that have become less common since the end of the 80's. And I think the scale of this detrimental damage increases the farther back you go.