The use of drugs is something that I would deem sinful, and also advise anyone with an addiction to seek help. I have some relatives that got involved and saw their lives be destroyed because of them. Masturbation, I believe is also a sin. Sex is a sacred beautiful act. It is meant to be both unitive and procreative. When one of these aspects taken away it ceases to be what God meant it to be and so is sinful. Masturbation is neither unitive or procreative, and is IMHO, and that of the Catholic Church a sinful behavior. Finally, treat all people with the love of Christ no matter what.