During a live CNN interview in 2010, former U.S. Surgeon General Joycelyn Elders stated, “Marijuana is not addictive, not physically addictive anyway.” Her point was that different types and degrees of addiction exist, and the physical addiction associated with heroin, crack and painkillers is not consistent with what cannabis abusers experience. As noted by Psychology Today in 2012, “The vast majority of those who use marijuana do so occasionally and exhibit no addictive symptoms—no increased tolerance, no cravings and no withdrawal.” Hence, cannabis is the most commonly consumed prohibited drug in the country—by a very wide margin—but most every other abused substance dominates it in terms of addiction rates.
So what exactly is physical addiction? Heavy drug use can lead to a physical dependence as brain circuitry adapts, natural neurotransmitter production drops and neural receptors shrink and/or desensitize, and dependence turns into physical addiction when the body can no longer function without the substance. For example, a drug like morphine floods the mesolimbic system with dopamine—the neurotransmitter that produces pleasure—and prompts a decrease in the production of natural chemicals (e.g., endorphins) and blunts their impact when they bind to receptors. As a result, the body needs regular substance intake to adjust for the change, and the amount escalates the longer the substance is abused. This process happens with most drugs of abuse, but it does not appear to occur with cannabis.
Physical addiction also involves more immediate health risks. For example, a person who takes benzodiazepine sedatives (e.g., Valium, Xanax, Klonopin) can develop a physical addiction in mere months, and abrupt cessation of use can result in fatal seizures. Similarly, opiate and alcohol withdrawal can involve severe symptoms like the shakes, nausea, vomiting, hallucinations and physical pain. Cannabis involves no such risks. Likewise, cannabis compounds bind to receptors that are comparatively sparse in the medulla, the part of the brainstem that manages the respiratory and cardiovascular systems. Opiates, sedatives and alcohol—but not cannabis—can significantly impact the medulla, and overloading the medulla can result in potentially fatal respiratory depressions (i.e., an overdose).
Simply put, cannabis affects the body differently than physically addictive substances like heroin, morphine, cocaine, crack, alcohol and prescription stimulants, opioids and sedatives, and suggesting that cannabis involves this type of addiction is blatantly misleading.