Over-reaction is a key to mental disabilities being a problem. Look for cues when dealing with anyone. It is easy to recognize when a person has drifted off track. Hyperemotional response, having nothing to do with what you are talking about with said person. Veering off-topic. This is a sure sign you are communicating with an unstable individual. Bigotry is perhaps the best tell. It is illogical and has no basis in reality/logic.