The casino employees aren't licensed psychic doctors, so they can't decide who is mentally sick and who is OK. I'm sure that if a guy starts acting weird, they will kick him out of the casino.
I assume that some physical signs can show that someone is not mentally stable. And I pointed to the fact that can such a person be barred from gambling based on some of these clear physical signs and not a psychiatric check.
Mentally deranged or unstable persons are well known for their violent behaviors of causing harm to others, they don't work for money neither have a sense to gamble for money but this man from the op does the opposite which makes me count him as not mentally unstable but as someone suffering from a depressive condition from life's challenges that had overwhelmed him making him to care less of himself
I don't think it is all mentally unstable people that are violent. I also feel that the ability to work and gamble is not a yardstick to conclude that somebody is sound. Many emotionally unbalanced people still work and are not violent.
Not all mentally unstable people are violent, some are so gentle and they have no sense of their environment, they are trapped in an illusion, and no matter what you say to them they will never get violent, but where I am confused is how such people will need money.
I doubt they will feel the need to take risks, there is one I know here, who knows the importance of money, but he prefers to ask people for money, the sense of hustling is no more in his mind, and even no one will want to hire such people.
I think the chances of mentality unstable people going into gambling is very limited, I have never seen such people in a online casinos, if they have families they are always with them for montiroing, such people can't be left alone most times as they can do something stupid.