Drugs by addiction potential (Max=100) 1 Nicotine (100) 2 Smoked methamphetamine (98.53) 3 Crack (97.66) 4 Methamphetamine injected (94.09) 5 Valium (Diazepam) (85.68) 6 Methaqualone (83.38) 7 Secobarbital (82.11) 8 Alcohol (81.85) 9 Heroin (81.80) 10 Oral Amphetamine (Crank) (81.09) 11 Cocaine (73.13) 12 Caffeine (72.01) 13 PCP (Phencyclidine) (55.69) 14 Marijuana (21.16) 15 Ecstasy (20.14) 16 Hallucinogenic mushrooms (17.13) 17 LSD (16.72) 18 Mescaline (16.72)