An analysis of past research has shown that cannabis consumption can lead to memory and learning problems lasting for several weeks.
Scott Isbell smoked marijuana since he was 17. He was struggling to set goals and meet deadlines at college by the time he was 19. He was losing friends and his grades dropped to A’s from B’s. He didn’t think any of this was important enough to quit marijuana, until he began theater classes.

Isbell, now 27, a Concord-based communications expert and producer of television, said that the class required him to act and remember things. It was embarrassing. It felt like I was playing catch-up. My brain was stuck.”


Isbell sought treatment at Boston Children’s Hospital’s Adolescent Addiction Program. There, doctors and therapists helped him reduce his cannabis use.

An current analysisof prior research on the effects of cannabis upon young people’s cognition showed that many of the previously known learning and memory problems — such as slow processing speed and difficulty focusing — can linger for several weeks. Researchers from the University of Montreal discovered that verbal learning, recall, and retention were particularly affected when the person’s level of consciousness is low.

Dr. Sharon Levy, a Harvard Medical School associate professor and director of the Adolescent Substance use and Addiction Program, Boston Children’s Hospital, stated that marijuana taps into the brain’s existing systems that use endocannabinoids. These are cannabis-like substances found naturally in the body. “When you consume cannabis you’re really flooding the system with the psychoactive plant chemical THC (tetrahydrocannabinol), which in the short term is really great at hijacking the brain’s reward system.”

Scientists are concerned about more than just the immediate cognitive issues. Scientists are also concerned about the long-term effects of cannabis use in teens and young adults.

Levy stated that there are numerous studies showing that cannabis-using young people have poorer outcomes in many areas of their lives, including academic and job performance. These studies are controversial because it is not possible to determine if cannabis causes bad outcomes, or if people who were destined for bad outcomes were drawn towards cannabis.

Levy stated that “the problem is that it’s not possible to do a randomized, controlled trial in which 100 children are told to smoke marijuana and 50 are told no.”

Some research suggests that states with legalized recreational cannabis use do not have higher rates for teen consumption. However, approximately 22 percent of U.S. high-school students have reported that they have used marijuana in the last 30 days according to the Centers for Disease Control and Prevention.

Staci Gruber, director at McLean Hospital’s Cognitive and Clinical Neuroimaging Core and Marijuana Investigations for Neuroscientific Discovery, (MIND), said that the brain is particularly vulnerable in adolescence. Gruber is also an associate professor at Harvard Medical School of psychiatry. He said that “anything can alter the trajectory of brain developmental.” It’s better for your brain to protect it from all things, not just cannabis. Parents should not say “no”, but rather “just not yet.”

According to Dr. Igor Grant (distinguished professor in the Department of Psychiatry, and director of The Center for Medicinal Cannabis Research at University of California, San Diego), not everyone believes cannabis has bad effects.

Grant stated that it was the whole chicken-and egg question. “Twin studies don’t show any differences between twins who began using and those who stopped. “So I don’t believe there are cognitive deficits such as long-term memory loss.

However, there are concerns about the short-term effects on teenagers and young adults, according to Dr. Nora Volkow (director of the National Institute on Drug Abuse).

Volkow stated that when you consider the effects of cannabis on teens, it is important to take into account, for instance, what happens if a teenager uses cannabis and fails a test. The teen may experience low self-esteem if they are exposed to many failures. The consequences of using the drug can be more severe than the immediate use.

Volkow reminds parents to be alert

She said, “If you notice a change in your child’s behavior, you should investigate it.” You should not assume that this is a normal teen behavior.

Experts warn that high-potency marijuana can cause brain damage in teens.

Carrie Cuttler is an assistant professor in psychology and director at Washington State University’s Health and Cognition laboratory. “The cannabis we have today is very different.” “Back in the day, cannabis contained only 3 percent of THC. Now we see as high as 90% in some samples.”

High dose cannabis products can cause vomiting that is severe enough to require hospitalization or episodes of psychosis. Levy was the researcher on a study that revealed almost half of teens had experienced paranoia and anxiety while using cannabis.


The answer to the question of cannabis chicken-and egg may soon be found. The Adolescent Brain Cognitive Development Study was launched by the National Institutes of Health in 2015. The study is currently tracking the brain, behavior, and biological development of 11,880 children ages 9-10. It will be available through adolescence, and even into young adulthood.

Parents who think their children are suffering from cognitive problems due to marijuana use should seek cognitive remediation therapy. Dr. Antoine Douaihy is an addiction psychiatrist and a professor of psychiatry at the University of Pittsburgh School of Medicine.

Douaihy stated that CRT is a behavioral-training-based intervention that improves the neuropsychological functions affected due to cannabis use. It includes attention span, memory and executive function. This is crucial for interpersonal relationships and social functioning.

Scott Isbell is in a better place, but he wishes he hadn’t tried cannabis.

He said, “It’s everywhere now in society.” “It’s difficult to break a habit once someone is hooked.”