In 2009, The Substance Abuse and Mental Health Services Administration conducted the National Survey on Drug Use and Health, and the results shed some light on the prevalence of marijuana use. Researchers discovered that in the year of the survey, around 16.7 million Americans over 12 smoked pot at least once in the month before they were polled.
It is the most widely used illegal drug in the United States, but there are still many pervasive misconceptions about marijuana. Among the most hotly-debated characteristics of the drug is whether or not it is physically or psychologically addictive. What makes the situation more conflated is that there is a considerable amount of literature supporting both sides.
To properly understand the addictive qualities of marijuana, it's important to be familiar with the effects of the drug. While most people are aware of the common side-effects including slowed reaction time, increased appetite and a distorted sense of time, there are a few more phsyiological effects that may be less widely-known. According to WebMD.com, marijuana also causes a rapid heart rate, increased blood pressure and an increased rate of breathing.
Before considering the implications of marijuana use in terms of addiction, users should also be aware of the health effects of the drug. According to the National Institute on Drug Abuse (NIDA), people who smoke marijuana experience a dramatic increase in the risk of heart attack for about an hour after smoking.
One area of contention that exists is whether or not smoking marijuana raises one's risk of developing lung cancer much the same way smoking tobacco does. While some studies have shown that marijuana smoke contains some carcinogenic hydrocarbons, scientists have been unable to find a positive link between the drug and the development of lung, upper respiratory or upper digestive tract cancers, according to the NIDA.
Many people who argue that marijuana is addictive point more toward a psychological dependence on the drug rather than the physical reliance that harder substances create. Specifically, WebMD says that one in 12 occasional users can experience symptoms of withdrawal including aggression, depression, anxiety and a decreased appetite.
But what causes the dependence might be a little more complicated than one might think. Many people know that marijuana's active ingredient, delta-9-tetrahydrocannabinol (THC), targets the cannabinoid receptors in the brain. However, according to Psychology Today it also can impact the opiod receptors as well, meaning it effects the same areas of the brain as heavily-addicting opiates. While this does not mean that smoking pot will make users addicted, it does speak to the fact that the drug has some similar characteristics to others such as heroin and pain-killers.
There have also been studies pointing to the fact that some people may be more at-risk to develop a psychological dependence on the drug. A 1998 study conducted by the University of Colorado School of Medicine that polled clinicians who treat younger patients found that adolescents who present symptoms of substance abuse disorder are more likely to exhibit a dependence on marijuana.
Of course, there are counter-arguments to the hypothesis that marijuana is addictive or on par with other more serious substances. Perhaps the most compelling argument from the other side is that the so-called "gateway theory," that smoking pot leads users to try harder drugs later in life, is mostly not true and at the very least overstated.
Researchers from the University of New Hampshire discovered that factors such as race, ethnicity, employment status and stress were much more indicative of whether a subject would move on to illicit drugs, not if they started smoking marijuana at a younger age.
"While marijuana use may serve as a gateway to other illicit drug use in adolescence, our results indicate that the effect may be short-lived, subsiding by age 21," the researchers wrote. "Interestingly, age emerges as a protective status above and beyond the other life statuses and conditions considered here."
Furthermore, even if there is evidence to suggest that marijuana is habit forming, the number of people who actually become addicted is relatively low. According to the NIDA about 9 percent of people who use marijuana will eventually become addicted to it but those who start using the drug in their teens become addicted at a rate of about 1 in 6. Still, the 2008 NSDUH report found that 15 percent of people who entered a drug abuse treatment program said that marijuana was their drug of choice.
Regardless of whether or not marijuana is addictive, there are many long-proven drawbacks to its regular use that could interfere with one's everyday life. In some cases it can lead to depression and decreased motivation, but according to United Health Services it can also interfere with the immune system.
More seriously, however, are some studies that have shown a link between smoking marijuana and developing significant psychological disorders. Specifically, a group of scientists from South Limburg Mental Health Research and Teaching Network discovered that marijuana use moderately increased the risk of psychotic symptoms in young people.
Additionally, several bodies of research have indicated that even moderate use of the drug can boost a person's risk of developing prolonged depersonalization disorder. In fact, in a recent study about 13 percent of people who have the condition say that it is triggered by marijuana use.
Despite the debate over its addictive qualities and health risks, a growing number of people are coming out in favor of legalizing marijuana. According to a recent Gallup poll, a record-high 50 percent of Americans said they were in favor of the measure in 2011, up slightly from the 46 percent who said the same in 2010. If one goes back even further, the rise is even more shocking. When Gallup first started asking the question in 1969, only about 12 percent of respondents favored legalization. Not surprisingly, members of the younger generation are more apt to be in favor of legalization with 62 percent of those between 18 and 29 answering in the affirmative.