An?l???? ?f th? ??rr?l?t??n b?tw??n the u?? ?f 18 v?r??u? ????h???t?v? ?ub?t?n??? shows 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 ?? a bridge in