As they are kinda hard to find, here they are :
lsd : models/smile/smile.mdl
alcohol : models/drug_mod/alcohol_can.mdl
shrooms : models/ipha/mushroom_small.mdl
weed : models/katharsmodels/contraband/zak_wiet/zak_wiet.mdl
water : models/drug_mod/the_bottle_of_water.mdl
meth : models/katharsmodels/contraband/metasync/blue_sky.mdl

There ya go guys, have fun (and don't do drugs kids)