Most doctors and psychologists seem to authentically believe in the concept of mental illness. Do they ever really take the time to grasp how seemingly impossible this is?

Most doctors and psychologists seem to authentically believe in the concept of mental illness. Do they ever really take the time to grasp how seemingly impossible this is? I seem to recall from my college psych classes (I got my degree in psychology) that there were a lot of stats about how mental illness exists differently culturally, in terms of rates of diagnosis, behaviors, and symptoms.