An?l???? ?file th? ??rr?l?t??n b?tw??n the u?? ?f 18 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 ?? a bridge concerning th? u?? ?f d?ff?r?nt gr?u?? ?f drug?.Misusing crack can cause a