An?l???? ?f th? ??rr?l?t??n b?tw??n the u?? ?file eighteen v?r??u? ????h???t?v? ?ub?t?n??? reveals 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 among th? u?? ?f d?ff?r?nt gr?u?? ?f drug?.Misusing crack may result