Marijuana: Should it be Legal? Is it Safe?

Regulation of Marijuana
Public opinion and public policy about marijuana for medical and recreational use are in flux and in the news.  The New York Times recently presented a series of articles on marijuana and called for legalization.  An influential physician and CNN's chief medical correspondent, Sanjay Gupta said that he had changed his mind and endorsed decriminalization and wider access to marijuana for medical reasons.  According to the Pew Research Center, public opinion has swung to a majority favoring legalization with fewer than 20% in favor in 1990 compared to 54% in favor in 2014.

Although federal law that considers marijuana an illegal drug remains unchanged, as of July 2014, thirty-five states and the District of Columbia permit some form of marijuana consumption for medical reasons, eighteen of these states and DC have also decriminalized possession of small amounts of marijuana and Colorado and Washington have legalized it for recreational use--a step that other states are considering.  In fact, about 74% of the U.S. population now lives in a state with relaxed marijuana laws.

This liberalization trend has gained momentum for several reasons, including the argument that the illegal drug trade that fosters criminal behavior, violence, and destruction of public lands could be decreased, the need to regulate a drug that’s availability and use is widespread, the possibility of tax income from sales, the unfairness of marijuana arrests (8.2 million between 2001 and 2010) and 20,000 to 30,000 incarcerated for selling or possession, the cost of drug enforcement estimated at $3.6 billion annually, and the lifelong harm of an arrest record to education, employment and eligibility for a loan or mortgage.

Because it can take up to 12 days for marijuana to leave the body, even with sporadic use and without a drug arrest, marijuana use can keep a person from getting a job because some employers test for drug use as part of the hiring process. And some companies do routine drug tests on employees, so people who use marijuana can lose their jobs.

The legal trends on regulation of marijuana use and possession are also fostered by the argument that marijuana is relatively harmless, especially compared to tobacco and alcohol, and that legal bans on use are futile, in that 30 million Americans use marijuana every year and 44% of teens have tried it at least once.

However, regular use among teens is much lower than ever use. According to the National Institute on Drug Abuse (NIDA)'s 2012 Monitoring the Future study, about 6.5% of 8th graders, 17.0% of 10th graders, and 22.9% of 12th graders had used marijuana in the month before the survey, and 6.5% of 12th graders reported using marijuana daily.

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Short-Term and Long-Term Effects of Marijuana
Although the public favors legalization and 60% of high school seniors do not think that regular marijuana use is harmful, marijuana (also know as cannabis) does have harmful short-term and long-term effects. Most are caused by the effects on the brain of the main active chemical in marijuana, THC (delta-9-tetrahydrocannabinol).   Older studies of the risk of marijuana may be less relevant because through selective plant breeding, the concentration of THC in marijuana has been increased nearly three times compared to supplies that were available as recently as 1995.

Short-Term Effects
When someone smokes or eats marijuana, THC enters the bloodstream and binds with cannabinoid receptors in the brain. When these receptors are in the parts of the brain that govern sensory perception and pleasure, it causes the marijuana "high."
THC also binds with receptors in other parts of the brain that affect thinking, memory, coordination, and concentration, and frequently causes unfavorable side effects, including:

  • difficulty with thinking and problem solving
  • problems with memory and learning including problems studying, learning new things, and recalling recent events.  These problems can last for days after use.
  • loss of coordination
  • distorted perception
  • an increase in appetite
  • feeling lightheaded or drowsy
  • a decrease in inhibitions that can lead to unsafe behavior such as risky sex or driving

Loss of coordination, and distorted judgment and perception can make driving unsafe.  According to the NIDA, studies in various locations found that approximately 4 to 14 percent of drivers who sustained injury or death in traffic accidents tested positive for THC.  The NIDA also noted several studies that found that marijuana use more than doubles a driver’s risk of being in an accident.  This can be compared to the overall risk of a vehicular accident that increases by a factor of 5 with a blood alcohol level of 0.08%, the legal limit in most countries.

In another study reported by the NIDA, researchers followed people from age 13 to 38.  They found that heavy users of marijuana in their teens who continued frequent use into adulthood had a significant drop in IQ, even if they quit.  Effects can also be unpredictable when marijuana is used in combination with other drugs but it is known that marijuana and alcohol potentiate the harmful effects of each of the drugs.

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  • Addiction (in about 9% of users overall or 2.7 million Americans, 17% of those who begin use in adolescence, and 25 to 50% of those who are daily users)*
  • Altered brain development including impaired neural connectivity*
  • Poor educational outcome, with increased likelihood of dropping out of school*
  • Cognitive impairment, with lower IQ among those who were frequent users during adolescence*
  • Diminished life satisfaction and achievement (determined on the basis of subjective and objective measures as compared with such ratings in the general population)*
  • Symptoms of chronic bronchitis, but a risk of lung cancer has not been established
  • An association with increased risk of anxiety, depression and chronic psychosis disorders (including schizophrenia) in persons with a predisposition to such disorders, but causality has not been established

* The effect is strongly associated with initial marijuana use early in adolescence.

Many people erroneously think marijuana is not addictive.  About 9 percent of people who use marijuana become dependent on it. The number increases to about one in six among those who start using it at a young age, and to 25 to 50 percent among daily users. By comparison, cocaine, a schedule 2 substance with supposedly less abuse potential than a schedule 1 drug like marijuana, causes 17% of those who use it to become addicted and 23% of heroin users become addicted. The addiction potential of tobacco is even worse, affecting an estimated 32% of smokers, many of whom go on to die because of their addiction.

People who use marijuana may also experience a withdrawal syndrome when they stop using the drug. It is similar to what happens to tobacco smokers when they quit—people report being irritable, having sleep problems, and weight loss—effects which can last for several days to a few weeks after drug use is stopped. Relapse is common during this period, as users also crave the drug to relieve these symptoms.

While most people who smoke marijuana do not go on to use other drugs, long-term studies of high school students show that few young people use other illegal drugs without first trying marijuana. For example, the risk of using cocaine is much greater for those who have tried marijuana than for those who have never tried it. Using marijuana puts children and teens in contact with people who use and sell other drugs. So, a person who uses marijuana is more likely to be exposed to and urged to try other drugs. The effects of marijuana on the developing brain of adolescents may also affect their likelihood of using other drugs as they get older.

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What About Medical Marijuana?
Under U.S. law since 1970, marijuana has been a Schedule 1 controlled substance. This means that the drug has no approved medical use. However 35 states and the District of Columbia have legalized marijuana for medical use even though it hasn’t been approved by the Food and Drug Administration (FDA) to be a medicine.  The purity and dosages of smoked marijuana are not likely to be consistent with good pharmacologic medical practice.  And most users of “medical” marijuana have no relevant medical condition that merits its use.

However, a recent comprehensive evaluation of the potential benefits of marijuana carried out by the institute of Medicine considered medications containing synthetic THC to be of value in treating severe pain, spasticity, nausea in cancer patients undergoing chemotherapy, and to stimulate appetite in patients with wasting syndrome—severe, involuntary weight loss—due to AIDS. 

What if a Person Wants To Quit Using Marijuana?
Currently, no medications exist for treating marijuana addiction. Treatment programs use behavioral therapies and a number of programs are designed specifically to help teenagers who abuse marijuana.  In addition to reaching out to talk to a parent, school guidance counselor, or other trusted adult, there are also anonymous resources, such as the National Suicide Prevention Lifeline (1-800-273-TALK) and the Treatment Referral Helpline (1-800-662-HELP).  The Treatment Referral Helpline is provided by the Substance Abuse and Mental Health Services Administration.  It refers callers to treatment facilities, support groups, and other local organizations that can provide help for their specific need.  Treatment centers can also be located by going to www.samhsa.gov/treatment.

Do Liberalized State Medical Marijuana Laws Increase Use?
States that changed their laws still prohibit use by anyone younger than 21. Studies in four states over a time period of up to 8 years are reassuring in that use of marijuana changed little in the first few years after the laws were enacted.  But there are some warning signs of trouble.  For example, edible products containing marijuana put children at risk.  Between 2005 and 2011 states that decriminalized marijuana saw a 30% increase per year in calls to poison control centers for children age 9 and younger who consumed marijuana products.  Also, the number of Colorado drivers in fatal motor vehicle who tested positive for marijuana increased after medical marijuana became commercially available in 2009. 

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Marijuana use is associated with substantial adverse effects, and can result in addiction. During intoxication, marijuana can interfere with cognitive function (e.g., memory and perception of time) and motor function (e.g., coordination), and these effects can have detrimental consequences (e.g., motor-vehicle accidents). Repeated marijuana use during adolescence may result in long-lasting changes in brain function that can jeopardize educational, professional, and social achievements.

As noted by Volkow and colleagues in the New England Journal of Medicine, “…the effects of a drug (legal or illegal) on individual health are determined not only by its pharmacologic properties but also by its availability and social acceptability. In this respect, legal drugs (alcohol and tobacco) offer a sobering perspective, accounting for the greatest burden of disease associated with drugs, not because they are more dangerous than illegal drugs but because their legal status allows for more widespread exposure. As policy shifts toward legalization of marijuana, it is reasonable and probably prudent to hypothesize that its use will increase and that, by extension, so will the number of persons for whom there will be negative health consequences.”

There is a reasonable concern that the trajectory of a burgeoning marijuana industry could mimic that of tobacco, with industrial production of easily available low-cost products, false claims of benefits and risk, and marketing to youth.  There is also concern that under an onslaught of lobbying to protect corporate interests, regulation will lag, as it did with tobacco.  The marijuana industry already has an advocacy organization—the National Cannabis Industry Association—to protect and advance its corporate interests.

The challenge to society is to avoid the widely recognized detrimental consequences of criminalizing marijuana possession and use, but to also recognize and minimize the negative consequences of marijuana for both individuals and society and recognize that these consequences are especially serious for young people.  To this end, better research to allow sound policies, better education of the public, especially teens, and avoidance of the commercialized free-market approach that has failed to protect the public from tobacco are indicated.

Here is Dr. Gupta’s advice: “Young, developing brains are likely more susceptible to harm from marijuana than adult brains. Some recent studies suggest that regular use in teenage years leads to a permanent decrease in IQ. Other research hints at a possible heightened risk of developing psychosis.  Much in the same way I wouldn't let my own children drink alcohol, I wouldn't permit marijuana until they are adults. If they are adamant about trying marijuana, I will urge them to wait until they're in their mid-20s when their brains are fully developed.”

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The New England Journal of Medicine: "Adverse Health Effects of Marijuana Use"

The New England Journal of Medicine: "Big Marijuana--Lessons from Big Tobacco"