I think it’s probably much more extreme than a baal teshuva. The vast majority of baalei teshuva do not stop being Frum and do not face the temptation to do so. On the other hand, my impression is that a recovered addict is never out of danger, and the temptation is always there.
Also, if they give in to their yetzer hora at all, they are in serious trouble. Whereas, in the case of a baal teshuva, if he gives in to his yetzer hora, he is no different than the rest of us who give in to their yetzer horas on occasion.