my son has been on invega for 2 months. He is tested by the court system for thc levels.. He has gained a lot of weight since taking the invega and had a drug test that came out clean and after not eating trying to lose wieght and riding his bike in weather in the 90's he tested dirty without using.. could this be a side effect? He's in jail now on a violation and i do believe him that he didn't smoke..