Marijuana contains over 400 different chemicals with the primary active ingredient being delta-9-tetrahydrocannabinol, or THC. The National Institute on Drug Abuse indicates that marijuana is psychologically addictive: Addicted users feel compulsive urges to seek and use the drug despite potential negative consequences. Although THC causes physiological effects, the addiction is not considered physical, in the sense that stopping the drug does not cause severe physical withdrawal. The chemical reward of THC causes pleasurable changes in mood, decreased feelings of stress, and enhanced appetite. These rewards occur during intoxication only and prompt people to obtain and use the drug repeatedly.
THC
Marijuana use causes temporary physiological changes. The psychoactive ingredient THC activates the cannabinoid receptors in the central nervous system. These receptors play a role in the reward pathway of the brain and when an interaction occurs between the brain and THC, the body senses a physiological reward, often in the form of euphoric mood, cessation of pain, and temporary relief of stress. According to the NIDA, because THC rapidly passes into the bloodstream and throughout the body, prolonged use of marijuana can permanently alter the brain's natural tendency to balance and regulate motivation and reward. In the event of marijuana cessation, for up to two weeks a person may become irritable, have disturbance of sleep and appetite, and have thoughts centered around obtaining the drug. This signifies craving, which is a property of psychological addiction that eventually subsides with long-term abstinence from marijuana.
Tolerance
"Tolerance" describes a condition in which a person gradually needs more and more of a drug in order to obtain the intoxicating effects. The NIDA describes tolerance as an addictive property of marijuana. Psychological dependence--per the Diagnostic and Statistical Manual criteria of seeking the drug despite the negative consequences of use and using a greater quantity of marijuana than originally intended--grows as drug tolerance increases. There is no specific time frame or quantity of marijuana that dictates when tolerance begins to occur, but regular and daily use of this drug will likely result in tolerance.
Rituals of Use
Rituals become a major part of the psychologically addictive nature of marijuana. The rituals can include obtaining the drug; using certain paraphernalia to smoke the drug, such as water pipes or rolling papers; and smoking the drug with other people. The Center for Substance Abuse Research notes that some users of marijuana tend to become euphoric before using the drug due to anticipation of its use. The rituals involved in marijuana use often lead to irritability during abstinence or recovery, as the user reminisces about the "good times" that accompanied smoking marijuana.
