Dependence Rating: 2.13
Because alcohol is legal and often consumed in social settings, alcohol addiction is complicated. But as an addictive agent, it’s remarkably simple—and effective. Alcohol’s withdrawal syndrome is so severe that it can cause death, and its effects on the brain’s reward system cause well-documented and intense craving in heavy drinkers. Regardless of the mechanism, 17.9 million Americans (7% of the US population) were classified as being addicted to or abusing alcohol in 2010.
Dependence Rating: 2.13
Cocaine prevents the reabsorption of dopamine in the brain’s reward areas. After you use enough blow, your brain reduces the number of dopamine receptors in this region, figuring it’s already got plenty of it. You can see where this is going. Because there are now fewer receptors, stopping the drug makes you crave it—after all, the body needs its dopamine. Cocaine doesn’t destroy dopamine neurons like methamphetamine, which makes its effect less powerfully addictive, but the fast method of use (snorting), short high (less than an hour) and rapid tolerance put it in the top ten.
Adderall users beware: Regular amphetamine (classified as pure or blended dextroamphetamine without methamphetamine, and including Adderall, Dexedrine, and Desoxyn) might not be quite as addictive as meth, but because it acts on the same reward circuit, it still causes rapid tolerance and desire for more if used regularly or in high doses. Quitting cold turkey can cause severe depression and anxiety, as well as extreme fatigue—and you can guess what extreme fatigue makes you crave…
Dependence Rating: 1.89
There’s a reason your doctor will tell you to taper off these prescription anti-anxiety drugs (Valium, Xanax, Klonopin, et al) after taking them for awhile. Each one increases the effectiveness of a brain chemical called GABA, which reduces the excitability of many other neurons and decreases anxiety. Because benzodiazepines cause rapid tolerance, quitting cold turkey causes a multi-symptom withdrawal that includes irritability, anxiety and panic attacks—enough to make just about anybody fall right back into benzo’s comforting arms.
Last on the list is a depressant and club drug that may itself be a neurotransmitter. It has cross-tolerance with alcohol—if you drink regularly, you’ll need to ingest more GHB to get high—as well as a short half life in the body and a brutal withdrawal syndrome that causes insomnia, anxiety, dizziness and vomiting. The combination is nasty: Take a lot of GHB to make up for your tolerance to alcohol and you could be hooked.