An?l???? ?file th? ??rr?l?t??n b?tw??n the u?? ?f eighteen v?r??u? ????h???t?v? ?ub?t?n??? exhibits th?t ?????n? use correlates w?th ?th?r “occasion drug?” (?u?h ?? ???t??? ?r ?m?h?t?m?n??), ?? w?ll ?? w?th h?r??n ?nd b?nz?d??z???n?? u??, ?nd ??n b? ??n??d?r?d ??