Steroids: The Easy Way To Destruction Athletes' use of steroids is very popular these days, but even though steroids do produce quick gains in muscle size, they also have some very serious side effects. After long-term use, steroids can cause a change in behavior, a decrease in the body's natural hormone production, and most seriously of all, addiction. One very noticeable characteristic of steroids use is a great chance in the behavior of the user. The major behavioral change is an uncontrollable aggression, in the form, most often, of the ....