Jon has used all the drugs a rockstar usually does, he just was never a addicted.
This is an interview of 1993, for a brazilian tv, where he admits that he has used pot and cocaine in the minute 39:36.
Jon was never a saint, he has spoken several times, and he was the frontman of one the biggest RnR bands in the last 30 years. I don´t know how some people refuses to believe that he has used drugs or betrayed his wife.