People have been debating whether or not marijuana is an addictive substance for decades. Addiction experts say yes, however many disagree insisting that it depends on your definition of “addictive.”The Diagnostic and Statistical Manual of Mental Disorders defines addiction as: “The compulsive use of a substance despite ongoing negative consequences, which may lead to tolerance or withdrawal symptoms once the substance is stopped.” Based on this definition alone at least 10% of those who use marijuana regularly are indeed addicted.In fact, according to Dr. Nora Valkow, the director of the National Institute on Drug Abuse, when a psychological addiction develops it results in a biological change in the brain. This is because there are different brain activities that involve the drive a psychological substance addiction after a person stops using. Dr. Volkow and other addiction experts also agree that a psychological compulsion to use is more powerful than the physical act of withdrawal. Crack cocaine addiction is a perfect example of this. This drug doesn’t result in the physical withdrawal symptoms, but its users can develop an extreme craving. The result is a very powerful psychological addiction.The active ingredient in marijuana is called THC. When you consume it, it connects with cannabinoid receptors in the brain. Cannabinoid receptors control sleep, mood and appetite. When you use marijuana, there is a lot taking place in your brain. The cannabinoid receptor system and the opiod receptor system being interacting at a higher level. Addiction experts state the activity of the opiod receptor system is what makes consuming THC in marijuana so pleasurable. Marijuana activates the same receptor system as opiod drugs like heroin, morphine and oxycotin. The opiod system then stimulates the dopamine reward pathway. The result is a rewarding and addictive experience, just as with other drugs.Another issue surrounding the marijuana addiction argument involves the issue of withdrawal. When many people think of addiction, they think of alcoholics or heroine junkies, vomiting and shaking as a result of withdrawal. Many people don’t consider marijuana addictive because it isn’t associated with these severe, physical symptoms commonly associated with withdrawal. Still, the majority of addiction experts agree that even if the addiction to marijuana is a psychological one, it is no less significant than a physical addiction.