Suggest Treatment For Anxiety And Anger Disorder

My son is a lovable person who shows lot of consideration for us.Once in-a-while, he becomes suspicious of us as if we have checked his belongings and found some of his secrets.He becomes very aggressive and shouts at us parents for 15-30 mins. Then he cools down and becomes normal in a couple of hours. He behaves as if nothing of that sort happened. He is 39 years, married for 3 years but single now and prefers to be single for life. How to understand his behavior and what kind of treatment will help him?