▁is ▁demonstrated ▁when ▁material ▁learned ▁under ▁one ▁State ▁is ▁best ▁re called ▁in ▁that ▁same ▁state . ▁A ▁study ▁by ▁Carter ▁and ▁Cass ady ▁( 1 9 9 8 ) ▁showed ▁this ▁effect ▁with ▁anti h ist am ine . ▁In ▁other ▁words , ▁if ▁you ▁study ▁while ▁on ▁hay ▁fe ver ▁table ts , ▁then ▁you ▁will ▁recall ▁more ▁of ▁what ▁you ▁studied ▁if ▁you ▁test ▁yourself ▁while ▁on ▁anti h ist am ines ▁in ▁comparison ▁to ▁testing ▁yourself ▁while ▁not ▁on ▁anti h ist am ines ▁after ▁having ▁studied ▁on ▁anti h ist am ines . ▁ ▁A ▁study ▁by ▁Block ▁and ▁Gh one im ▁( 2 0 0 0 ) ▁found ▁that , ▁relative ▁to ▁a ▁matched ▁group ▁of ▁health y , ▁non - d rug - using ▁controls , ▁heavy ▁mar iju ana ▁use ▁is ▁associated ▁with ▁small ▁but ▁significant ▁imp air ments ▁in ▁memory ▁retr ieval . c ann ab is ▁indu ces ▁loss ▁of ▁internal ▁control ▁and ▁cogn itive ▁imp air ment , ▁especially ▁imp air ment ▁of ▁attention ▁and ▁memory , ▁for ▁the ▁duration ▁of ▁the ▁into xic ation ▁period . ▁ ▁Stim ul ants , ▁such ▁as ▁c oca ine , ▁am ph et am ines ▁or ▁c aff e ine ▁are ▁known ▁to ▁improve ▁recall ▁in ▁humans . ▁However , ▁the ▁effect ▁of ▁prolong ed ▁use ▁of ▁stim ul ants ▁on ▁cogn itive ▁function ing ▁is ▁very ▁different ▁from ▁the ▁impact ▁on ▁one - time ▁users . ▁Some ▁research ers ▁have ▁found ▁stim ul