Dear Welcome to HCM We understand your concerns I went through your details. I suggest you not to worry much. We must know what is normal and what is abnormal. You said your father behaves abnormally at certain times when he is under stress. Till this point, that is OK. Almost everyone does so. Then you said, at that abnormal period, your father talks to himself and laughs to himself. That matter is a bit troublesome. Here you must confirm, whether the self speech and laugh, are continuation of the incident or they have no connection with the incident. If in connection, just counseling and training to overcome stress may be used. Other wise, you should take your father to a psychiatrist. If you require more of my help in this aspect, Please post a direct question to me in this website. Make sure that you include every minute details possible. I shall prescribe some psychotherapy techniques which should help you cure your condition further. Hope this answers your query. Available for further clarifications. Good luck.