To rank today's commonly used drugs by their addictiveness, we asked experts to consider two questions: How easy is it to get hooked on these substances and how hard is it to stop using them? Although a person's vulnerability to drug also depends on individual traits -- physiology, psychology, and social and economic pressures -- these rankings reflect only the addictive potential inherent in the drug. The numbers below are relative rankings, based on the experts' scores for each substance:
| 100 | Nicotine |
| 99 | Ice, Glass (Methamphetamine smoked) |
| 98 | Crack |
| 93 | Crystal Meth (Methamphetamine injected) |
| 85 | Valium (Diazepam) |
| 83 | Quaalude (Methaqualone) |
| 82 | Seconal (Secobarbital) |
| 81 | Alcohol |
| 80 | Heroin |
| 78 | Crank (Amphetamine taken nasally) |
| 72 | Cocaine |
| 68 | Caffeine |
| 57 | PCP (Phencyclidine) |
| 21 | Marijuana |
| 20 | Ecstasy (MDMA) |
| 18 | Psilocybin Mushrooms |
| 18 | LSD |
| 18 | Mescaline |
Research by John Hastings
Relative rankings are definite, numbers given are (+/-)1%
