There are no such rules in physical casinos where people can participate on the basis of category. Casinos or gambling sites, of course, must provide opportunities for all categories of people to participate and create an environment, but there is a rule-based requirement of gambling that age-based categories, especially school and college students below 18 years of age, cannot participate. But I have never seen a casino where mentally disordered gamblers participate.  However, I have never seen a casino that has any rules to prevent a mentally disordered or unstable person from participating.
However, most of today's gambling and casino sites are operated online. There is no way to check who or who participates, and in that case, if a mentally unstable person participates. Because there is no opportunity to directly participate in the casino in online casinos, in this case, any gambler or casino site can participate from any part of the world at any time. In this case, the physical condition of any participant is not taken into consideration.