“Okay, but this drug isn’t addictive… it’s all natural!” is what many believe about marijuana, colloquially known as pot, weed, and grass. In the United States, around 19% of Americans, nearly 52.5 million people, reported using cannabis at least once in 2021. Within a month, over 7.5% of the population, 19.8 million people, admitted to consuming marijuana. These statistics have risen greatly from the 90s, when a mere 4% of Americans used the drug. But what is marijuana—and is it really as benign as advertised?
The marijuana plant contains many cannabinoids, with the two most detrimental being delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the main psychoactive component of cannabis—it’s what makes people feel “high” when they consume cannabis. CBD, on the other hand, does not have psychoactive properties, and thus does not create the “high” feeling that THC does. Although unsure, scientists’ current hypothesis is that CBD works by slowing “down signals to your brain,” lowering inflammation and changing “the level of calcium in your brain cells,” which is important for communication between cells. THC releases dopamine and triggers the portion of your brain that responds to pleasure, giving users a “euphoric feeling.” Generally, CBD from hemp is federally legal, while THC is only legalized in certain states, and often requires a prescription.
Why a prescription? Typically, the marijuana legalized in states is medicinal marijuana, meaning it’s used for treating medical conditions. In patients with multiple sclerosis, medical marijuana shows to provide similar symptomatic relief as over-the-counter medications since cannabinoids have beneficial effects on the cells affected by multiple sclerosis. Furthermore, in some patients receiving chemotherapy treatments, THC-related agents have lessened chemotherapy-induced nausea and vomiting symptoms. In fact, THC-based medications were even more effective than alternative antiemetics for patients enduring moderate emetogenic chemotherapy. Many also utilize marijuana for chronic pain relief—in Colorado in 2014, 87% of medical marijuana ID cardholders listed “‘severe pain’ as a medical condition.”
However, marijuana’s health benefits don’t subdue its severe adverse effects, both physically and mentally, and especially on recreational users. Habitual marijuana smokers score lower values in tests for airway conductance, suggesting that smoking marijuana may cause significant issues in large airways, such as the lungs. Long-term smoking also often causes greater respiratory symptoms “suggestive of obstructive lung disease.” Plus, long-term cannabis users experience reduced hippocampal—the part of the brain responsible for memory—volume and neurochemistry. Fortunately, studies have shown CBD to have certain neuroprotective properties, possibly protecting partially against the negative effects of THC.
Mentally, even short-term cannabis consumption harms cognitive functions such as memory, attentional control, and motor inhibition. On tests of memory and attention, long-term users performed significantly worse than controls and shorter-term users; they recalled fewer words on the Rey Auditory Verbal Learning Test [Figure 1] and showed impaired learning and retention. Both short-term and long-term consumers executed time estimation tasks poorly in comparison to non-users. Additionally, although used frequently as an escape from poor mental health, frequent cannabis use in teenagers predicts an almost two-time increase in risk for depression and anxiety later in life.
Figure 1.
Nevertheless, despite the dangers of marijuana, teenagers are increasingly abusing the drug. As of 2021, “8.3% of 8th graders, 19.5% of 10th graders, and 30.7% of 12th graders” reported using cannabis in the past year. As the brain is developing, it is substantially more vulnerable to THC. This is especially concerning due to cannabis’ serious effect on brain development, impairing neural connectivity in parts of the brain involved in alertness and self-conscious awareness (precuneus), and learning and memory (fimbria). These impairments in brain connectivity may explain the association between significant declines in IQ and frequent marijuana consumption in adolescents as they grow up. As with other drugs, the younger one delves into marijuana, the higher the chance they will develop an addiction or dependence on drugs in adulthood—17% (or 25-50% if marijuana is consumed daily) of teens become addicted when experimenting with marijuana. The increased rates of cannabis addiction coincide with increasingly neutral and positive perceptions of marijuana: youth in the San Francisco Bay Area are more likely to see smoking marijuana similar to a hobby or sport, and the drug is generally seen by teens as safe to use. The perception of safety around the drug could be attributed to the progressive legalization of medical marijuana in the United States. One study has found an association with a states’ legalization of marijuana and adolescent use of the drug. In states with restrictive cannabis laws, the number of first-time users in the 12-17 year age group are significantly lower than states with marijuana-supportive laws.
“But back in my day…” Back in the 1960s to 1980s, the THC content of most marijuana hovered around or less than 2%. In contrast, today’s marijuana plant strains have a THC range of 17-28%, and produce little CBD (which has protective properties, so the lack of it is generally disadvantageous). Some concentrated THC products can even have upwards of 95% THC. The drug today has mutated into a much more dangerous and addictive drug than the one originally believed to be “harmless” and “safe.”
With the prevalence of the drug in today’s youth and the lack of significant research into its short- and longer-term effects, the accessibility of marijuana poses serious concerns to society. Although it has medicinal benefits for certain conditions, for the recreational consumer, cannabis can cause damaging health effects. If you consume marijuana, and experience cravings for it, give up important social activities for it, and/or feel withdrawal symptoms from cutting back on cannabis use, it’s likely you’re addicted. You can find a local treatment facility and support group by calling 1-800-662-HELP (4357) or visiting findtreatment.gov. “This drug” is both addictive and harmful—not the health secret many try to market it as.