Can you get mental illness when practicing qigong? Or is practicing certain skills harmful to people's minds?
The purpose of practicing martial arts is to be healthier. Scientific and reasonable martial arts practice will not get sick at all, but also prolong life and make your mind clearer.
But if you can't practice martial arts, you will be possessed. Mental illness is one of the manifestations of possessed, such as Ouyang Feng in the novel.
Therefore, it is very important to practice step by step and persistently.