 According to flashbacks in "The Parts in the Sum of the Whole," he only started to the kick the habit after meeting (and subsequently asking out) Bones for the first time while working a case together.As of the series pilot, he has been clean after attending GA meetings and has been able to resist the urge on several occasions when a case required him to be at a casino or a similar environment.In several episodes he can be seen twirling a poker chip (sometimes his GA sobriety chip) or playing with dice.