This Is Your Teen’s Brain on Marijuana
Parents should be aware that the marijuana being sold today, legally or illegally, is not the same as what was used in the 1960s and 1970s. Instead, today’s marijuana can have a real impact on the development of their child’s most precious resource, the growing brain.
Marijuana has been featured all over the news in recent months. Many questions about marijuana’s negative effects, possible medical value, and its safety and use have surfaced in the face of evolving legislation and changing cultural attitudes. It is even legal for recreational use in two states, Colorado and Washington.
With so many adults having legal access, it is likely more teens will be finding it easier to get marijuana, and more will try it. In fact, national surveys are showing that fewer teens perceive marijuana as harmful.
So what do parents tell their teens about the safety of marijuana in a changing world?
Marijuana, Memory, and Brain Health
First, parents can tell their teens that public health experts are worried about the effects of marijuana on the developing teen brain. We all know that people who smoke marijuana have temporary difficulties with memory and judgment. But science shows us that regular use by a teenager can affect thinking and memory for a long time, or even permanently.
Some examples of the science:
- A recent study of marijuana users showed that those who began using in their teens had substantially reduced connectivity among brain areas responsible for learning and memory.
- A large, long-term study in New Zealand showed that people who began smoking marijuana heavily in their teen years lost an average of 8 IQ points between ages 13 and 38, even when they stopped using as an adult. Those who started smoking marijuana in adulthood did not show significant IQ declines, which underscores the vulnerability of the teenage brain. With more than 6 percent of high school seniors smoking marijuana daily, they are putting their futures in jeopardy.
It’s Not Your Mom and Dad’s Marijuana, Kids
The cultural evolution of marijuana mirrors the agricultural evolution of the marijuana plant. Marijuana causes a “high” by interfering with the parts of the brain that influence pleasure, memory, thinking, concentration, sensory and time perception, and coordinated movement. The most psychoactive, or mind-altering, chemical in the marijuana plant is delta-9-tetrahydrocannabinol, or THC.
When today’s parents and grandparents were teens, THC levels were relatively low, about 3 to 4 percent. Today’s THC levels are much higher, now an average of nearly 13 percent – which has left many people with side effects so unpleasant that they end up in America’s emergency rooms, with more than 900,000 visits last year. Users can experience side effects that include altered perceptions and mood, impaired coordination, difficulty with thinking and problem solving, and disrupted learning and memory.
For Some, Marijuana Has Potent Mental Health Effects
For regular marijuana users, mental health problems are also a possible side effect. High doses can produce a temporary psychotic reaction (involving hallucinations and paranoia) in some users, and use of marijuana can have worsening effects on existing schizophrenia. A series of large studies following users across time also showed a link between marijuana use and later development of psychosis. This relationship was influenced by genetic variables as well as the amount of drug used, drug potency, and the age at which it was first taken. Those who started using marijuana at a young age are at an increased risk for later problems.
Science has also found links between marijuana use and other mental health problems, such as depression, anxiety, suicidal thoughts among adolescents, and personality disturbances, including a lack of motivation to engage in typically rewarding activities.
The Social Science on Teens and Marijuana
While marijuana can temporarily relax a person and relieve stress, science tells us that long-term regular use does not generally improve lives.
- Heavy marijuana users report lower life satisfaction, poorer mental and physical health, more relationship problems, and less academic and career success compared to non-marijuana-using peers.
- For teens, marijuana use is associated with a higher likelihood of dropping out of school.
- Marijuana use at all ages is linked to traffic accidents and fatalities.
Public health experts are aware that components in the marijuana plant might have therapeutic potential, and research is underway to learn more about these healing effects. However, the real promise for any medicinal effects of marijuana is not in the whole smoked plant, but instead in some of its non-psychoactive components, which can be extracted and developed into medicines. You can find more information about the potential of medicinal marijuana on the National Institute on Drug Abuse (NIDA) Web site.
About the Author
Jack B. Stein, PhD, is director of the Office of Science Policy and Communications (OSPC) within NIDA, part of the National Institutes of Health (NIH). OSPC leads science policy, strategic planning, program evaluation, communications, and public liaison activities. Dr. Stein has more than two decades of professional experience in leading national drug- and HIV-related research, practice, and policy.
Published May 17, 2014
By Jack B. Stein, PhD, Special to Everyday Health