1. Is Marijuana addictive?
Studies that attempt to answer this question have controversial results. While marijuana use is linked to dependance, it is possible to be dependant without being addicted. However, using the term dependant rather than addicted, around 9 percent of people who use marijuana will become dependant on it (with the percentage nearly doubling for those who begin use in their teens).
People who report regular use say that irritability, restlessness, issues with appetite, and/or physical discomfort occur within a week of quitting and may last for two weeks.
2. Does Marijuana have long term effects on the brain?
Studies suggest that marijuana has the most serious, long-term effects on young people such as those who were exposed before birth, soon after birth, and into adolescence. One study showed that regular use during adolescence resulted in significantly lower IQ scores. The individuals in the study did not regain these IQ scores upon quitting use in adulthood.
Though studies have shown that regular use among young people does have long term effects on the brain, the effects marijuana has on the adult brain is hard to measure because study participants often use multiple substances. However, the National Institute of Health is currently funding a study that may have more conclusive answers.
3. Does Marijuana use have an effect on lung health?
Smoking marijuana, like smoking tobacco, is an irritant to the lungs and throat. Smoking marijuana can cause a heavy cough during use, but it also contains levels of volatile chemicals and tar. Since these chemicals and tar are similar to tobacco smoke, concerns have been raised about risk for cancer and lung disease. Smoking marijuana may also reduce the respiratory system’s immune response, increasing the likelihood of the person acquiring respiratory infections, including pneumonia.
Marijuana smoking is connected with inflammation, airway resistance, and lung hyperinflation. Those who smoke marijuana regularly report more chronic bronchitis than those who do not smoke--this leads to more outpatient medical visits. It has been suggested that THC has immune-suppressing effects, which would lead to an increase in infections such as pneumonia.
Though the connection between smoking marijuana and lung cancer is still being studied, marijuana does contain carcinogenic combustion products (including about 50% more benzoprene, 75% more benzanthracene, and more phenols, vinyl chlorides, and nitrosamines) than cigarette smoke. The differences in the way tobacco and marijuana are smoked make it difficult to compare the long-term effects of smoking each substance. Another factor which makes comparison difficult is that many people use both marijuana and tobacco.
4. Is Marijuana safe or effective as medicine?
The medical properties of marijuana and its components have been the subject of debate for decades, but within the past decade, the debate has become more streamlined. THC's medical benefits have been proven in particular formulations: The U.S. Food and Drug Administration (FDA) has approved THC-based medications (Marinol® and Cesamet®) for the treatment of nausea in patients being treated with chemotherapy. Epidiolex®, a CBD-based, FDA-approved medication, has been used to treat two forms of severe childhood epilepsy. These medications are delivered to patients in a reliable dosage form and through a reproducible route of delivery to ensure that patients derive the anticipated benefits. Several other marijuana-based medications are currently undergoing testing.
An important factor to keep in mind is that medications such as these use purified chemicals derived from or based on those in the marijuana plant. This means that they have more promising therapeutic effects than use of the whole marijuana plant or its crude extracts. It is difficult to develop drugs from botanicals (such as marijuana). Botanicals contain hundreds of unknown, active chemicals, and developing a medication with consistent and accurate doses of chemicals is incredibly challenging. Additionally, there are adverse health effects of smoking and THC-induced cognitive impairment.
There are many additional concerns with "medical marijuana" because little is known about long-term impact--especially by people with health- or age-related vulnerabilities. Further research must be done to determine if people with health disparities are at greater risk for adverse health outcomes from marijuana use.
5. Is Marijuana a "gateway drug"?
Some research suggests marijuana is likely to precede other substance use as well as the development of addiction to other illicit and licit substances. A study from the National Epidemiological Study of Alcohol Use and Related Disorders found that adults who used marijuana were more likely than those who had not to develop an alcohol use disorder in less than 5 years. In addition to alcohol use, marijuana use is also related to other substance use disorders such as nicotine addiction and drugs such as morphine. Though these findings are consistent with the idea of marijuana as a "gateway drug," the majority of people who use marijuana do not go on to use other illicit substances. The phenomenon called cross-sensitization where the continued use of one substance yields the same heightened behavioral response as the introduction of a new drug is not unique to marijuana. Alcohol and nicotine also prime the brain for a heightened response to other drugs and are, like marijuana, also typically used before a person progresses to other, more harmful substances.
It is vital to note that factors such as a person's social environment are also at play. These environments are critical to a person's risk for drug use--just as biological mechanisms are. Instead of using a gateway-drug hypothesis, some researchers believe that people who are more vulnerable to drug use are more likely to begin use with substances that are readily available (such as marijuana, tobacco, or alcohol). Frequent social interactions with others who use drugs then increases that person's chances or trying other drugs. Though more research needs done to explore this question, it is likely that both social and biological factors are at play.