what can be the cause of addictive behavior?

Hi, my brother has been acting weird lately and I would like to know what is going on. I think that he has bee using some narcotics and that he tried to stop with that. I guess he never wanted to tell anyone about that. He vomited, had a fever for few days, he sweated a lot… Are those symptoms of addictive behavior, are drugs the cause?

Well, I guess you should confront him and ask directly what is going on. You are brothers so I guess he will tell you at one point. Anyway, addictive behavior could easily be the result of taking narcotics, various stimulants, different pills etc. With drugs, often as a result of stopping taking them, some withdrawal effects will occur and those are the ones you have mentioned and several other more.