What disorders do you have in mind? What severity? People who are truly broken from reality, i.e. psychotic would have a hell of a time playing s video game for any length of time.
How much do you know about abnormal psychology? There are various degrees of disconnection from reality. People with Borderline Personality Disorder can be highly functional, even highly acclaimed in their field, yet have demonstrable, stark disconnects from reality. There's a lot of room between a nominal psychology and an extreme Schizophrenic.
Whatever Devin Moore had would certainly qualify. However, the waters are muddied by his court case. (The defense's claim is PTSD, but that might have more to do with defense tactics than accuracy of diagnosis.)
People with disorders is incredibly broad, as is the second part of your description.