Why Have Marijuana Use Disorders Doubled in the Past Decade?

A new study reports that marijuana use more than doubled in the past decade. Between 2001 and 2013, the number of adults who used marijuana in the United State increased from 4.1 percent to 9.5 percent.

The researchers also identified a substantial increase in marijuana use disorders or "cannabis use disorder" (CUD) during this time period. The researchers estimate that 3 of 10 current marijuana users have a cannabis use disorder.

Cannabis is defined as any of the various parts of the hemp plant, cannabis sativa, from which marijuana, hashish, and similar mildly euphorogenic and hallucinogenic drugs are prepared. The terms "cannabis" and "marijuana" are often used interchangeably.

In 2013, Cannabis Use Disorder was recognized in the fifth version of the Diagnostic and Statistical Manual of Mental Disorders. With the publication of DSM-5, cannabis abuse and dependence are now considered part of the same substance use disorder, or simply, cannabis use disorder.

A Brief History of Marijuana Prohibition and Legalization

Marijuana was legal in the United States until 1937, when Congress passed the Marijuana Tax Act which made cannabis illegal. At the time, the American Medical Association (AMA) opposed the legislation prohibiting the legal use of marijuana for medical purposes. Prior to the prohibition of Marijuana in 1937, cannabis had been recognized as a medical drug and marketed as an extract or tincture by a variety of pharmaceutical companies for treating ailments such as anxiety and lack of appetite.

Despite the medical establishment's opinion that cannabis had medicinal benefits, in 1970, the passage of the Comprehensive Drug Abuse Prevention and Control Act classified marijuana as a Schedule I drug. This classification of drugs are deemed to have a high potential for abuse and federally denied from being written as prescriptions by doctors. Other Schedule I drugs include: Heroin, LSD, Mescaline, Psilocybin, Bath Salts, MDMA (Ecstasy), Khat, and GHB.

Tetrahydrocannabinol, or THC, is the active ingredient in marijuana that makes you high. THC is still considered a Schedule 1 drug at the Federal level by the DEA, even though some U.S. states have legalized marijuana for recreational and/or medical use.

In the past decade, U.S. laws and attitudes towards marijuana across the country have become more relaxed and cannabis use has become more commonplace. Marijuana is currently legalized for medical purposes in 23 states and for recreational use in 4 states and the District of Columbia.

Marijuana legalization and cannabis use for recreational and medicinal puposes is a complex issue that stirs up passionate repsonses. Public opinions about cannabis on both sides of the aisle continue to create heated debates. Of all the health issues that I write about for Psychology Today, nothing is more controversial than the topic of marijuana. Anything I say about cannabis inevitably illicits adamant responses from readers.

Cannabis Use Disorders Have Doubled in Tandem with Increased Marijuana Use

The October 2015 study, “Prevalence of Marijuana Use Disorders in the United States Between 2001-2002 and 2012-2013,” was published online by JAMA Psychiatry. For this study, researchers compared data from face-to-face interviews with over 43,000 U.S. adults between 2001 and 2002 to data from over 36,000 people collected between 2012 and 2013.

The number of marijuana use disorders grew in tandem with the number of users, growing from 1.5% of the adult population in 2001-2002 to 2.9% in 2012-2013. Three of every ten Americans (30.6%) who used marijuana in the past year were categorized with a marijuana, or cannabis use disorder.

The experts attribute the rise in marijuana use disorders directly to the increase in the number of marijuana users. These findings are consistent with other studies which found an increase in cannabis-related emergency room visits and fatal car crashes associated with cannabis use. The experts caution that if the prevalence of U.S. marijuana users increases, so will the number of individuals at risk for cannabis-related problems.

More Middle-Aged and Older People Are Using Marijuana Since 2001

Interestingly, it appears that 45-64 year olds have been using significantly more marijuana in the past decade. Why would middle-aged and older adults show an increase in marijuana use? The researchers hypothesize that this could be a result of medical marijuana laws having little effect on adolescent recreational marijuana use.

In an April 2015 Psychology Today blog post, "The Psychological Damage of Alcohol Abuse Can Be Lethal," I wrote about a study from from the University of Washington published in the American Journal of Public Health which found that binge drinking in the United States has also dramatically risen in the past decade.

On average, heavy drinking among Americans rose 17.2 percent between 2005 and 2012, largely due to rising rates among women. Across the nation, binge drinking among women increased more than seven times the rate among men. The researchers suggest that women’s drinking habits have evolved as a reflection of changes in "social norms," but the reasons are probably much more complex. The same could be true for the increase in cannabis use during this similar period.

Other demographic increases in the past decade for cannabis use included especially large numbers of women, blacks, Hispanics, and southerners. In a press release, Deborah Hasin, PhD, professor of clinical epidemiology at the Mailman School of Public Health and Columbia University Medical Center said,

"At a time when Americans increasingly view marijuana use as harmless and favor its legalization, our findings suggest the need for caution and more public education about the potential for harms is warranted. This information is important to convey in a balanced manner to health professionals, policy makers and the public as the U.S. continues to consider legalization."

This call-to-action by Hasin et al is the primary reason that I am writing this blog post. In terms of public opinion, the pendulum appears to have swung too far towards a misconception that marijuana is not only harmless, but may in fact be “good for you." Obviously, cannabis has valid medicinal purposes. However, from the research I’ve done, and my personal experience, I believe that chronic or heavy use of marijuana is often detrimental.

Cannabis Vs. Endocannaboids (Self-Produced Cannabis)

In a January 2014 New Yorker interview, "Going the Distance," President Obama commented on his own marijuana use saying, "As has been well documented, I smoked pot as a kid, and I view it as a bad habit and a vice, not very different from the cigarettes that I smoked as a young person up through a big chunk of my adult life. I don’t think it is more dangerous than alcohol." Obama elaborated that he believed marijuana was actually less dangerous than alcohol "in terms of its impact on the individual consumer."

I smoked a ton of pot when I was in high school. For me, marijuana and other substance abuses exacerbated my dysphoria and lack of motivation as an adolescent and almost caused me to implode. At the time, there was little anyone could say or do to dissuade me from using drugs until I decided it was time to stop on my own volition.

The reason I stopped using marijuana was primarily because it made me depressed, unmotivated, spaced out, and at times paranoid. My decision to stop smoking weed was also motivated by my discovery of a runner's high and endocannabinoids. Whereas marijuana made me feel lethargic and hollow inside, endocannabinoids made feel energized and alive.

When I started running at age 17, I realized that a natural “runner’s high” made me feel infinitely better than bong hits. In a very obvious transition, I began substituting a THC marijuana high with an endocannabinoid runner’s high. The win-win consequences of endocannabinoids—which are your body's self-produced cannabis—create an upward spiral of both positive emotions and well-being.

On the flip side, I personally believe that, chronic cannabis use has the potential to create a downward spiral of depression, cognitive impairments, and amotivational syndrome. If you’d like to read more about the latest science behind runner’s high, check out a Psychology Today blog post I wrote earlier this month titled, “Is Runner’s High Our Evolutionary Antidote for Laziness?”

Today's Marijuana Has THC Potency Levels Close to 30 Percent

The laboratories that test the chemical composition of various marijuana plants paint a potentially alarming picture of today's cannabis crops. Over the past year, Andy LaFrate, Ph.D., and colleagues in his Colorado lab have been testing various marijuana samples. They have identified three major areas for concern: potency, amounts of a substance called CBD, and contaminants in cannabis products.

"As far as potency goes, it's been surprising how strong a lot of the marijuana is," LaFrate says. "We've seen potency values close to 30 percent THC, which is huge." LaFrate is the president and director of research of Charas Scientific, one of eight labs certified by Colorado to do potency testing.

Lafrate explains that three decades ago, THC levels were well below 10 percent. The THC content of cannabis has tripled in some strains because producers have been cross-breeding them over the years to meet user demands for higher potency. On the flip side, the levels of CBD, which yield many of the potent health benefits of marijuana, have been minimized in many strains. Also, the level of contaminants in cannabis products is relatively high and is currently unregulated.

Below is a YouTube video of LaFrate describing the findings of his laboratory:

Conclusion: Cannabis Is Big Business. Greed Could Override Public Health and Safety Concerns

Inevitably, all forms of marijuana legalization increase the availability of marijuana and impact public opinion towards cannabis use. Surveys show that more Americans are in favor of marijuana legalization than ever before, and fewer people consider marijuana use to be a health risk.

There is also growing concern that increased legalization for recreational marijuana use will be driven by financial interests of both marijuana sales and tax revenues. This could increase both use and abuse among people of all ages. Again, I feel an obligation to speak up about the potential risks of excessive acute or chronic cannabis use.

For example, in 2014, the National Highway Traffic Safety Administration's Roadside Survey of Alcohol and Drug Use by Drivers found the number of drivers with alcohol in their system has declined by nearly one-third since 2007. However, that same survey found that from 2007 to 2014 the number of drivers with marijuana in their system grew by nearly 50 percent. A different 2011 study found that marijuana use doubles the risk of accidents for drivers under the influence.

There is also a growing concern on the impact of heavy marijuana use on the structure and function of the developing brain. In a study published in December 2013, scientists at Northwestern Medicine discovered that the developing teenage brain may be particularly vulnerable to excessive marijuana use. The researchers found that teens who smoked marijuana daily for about three years had abnormal changes in their brain structures related to working memory and performed poorly on memory tasks.

Deborah Hasin, and her colleagues from Columbia University Mailman School of Public Health concluded,

"In summary, while many in the United States think prohibition of recreational marijuana should be ended, this study and others suggest caution and the need for public education about the potential harms in marijuana use, including the risk for addiction. As is the case with alcohol, many individuals can use marijuana without becoming addicted. However, the clear risk for marijuana use disorders among users (approximately 30 percent) suggests that as the number of U.S. users grows, so will the numbers of those experiencing problems related to such use. This information is important to convey in a balanced manner to health care professionals, policy makers and the public."

The researchers recommend using the lessons learned from alcohol and nicotine as models to shape laws and policies (eg, minimum legal drinking age and smoke-free laws) regarding cannabis use. I believe strongly that advocating for public health interests and educating policy makers and the public about the risk of cannabis use disorders and other consequences of chronic marijuana use is of paramount importance.

If you'd like to read more about this topic, check out my Psychology Today blog posts,

• "Does Long-Term Cannabis Use Stifle Motivation?"
• "Why Are Cannabis Users Susceptible to Memory Distortions?"
• "Cannabis Targets Receptors in the Amygdala Linked to Anxiety"
• "Casual Marijuana Use Linked to Brain Changes in Young Adults"
• "Heavy Marijuana Use Alters Teenage Brain Structure"
• "Why Do Teens Assume Vaping and Smoking Marijuana Is Harmless?"
• "Cannabis Addiction Is Linked to Higher Levels of Cortisol"
• "Is Runner's High Our Evolutionary Antidote for Laziness?"

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