New Dimensions Day Treatment Centers

Effects of Marijuana on the Teen Brain

Feb 23, 2021 | Adolescent Treatment, Addiction, Marijuana, Substance Abuse

Marijuana is the second most commonly used illicit substance for teens today. The acceptance of casual marijuana use has been growing in recent years. But teens are at a higher risk because of brain development that occurs at their age. Experts see the potential for lifelong problems with heavy marijuana use. More research is needed to know for sure, but there are good reasons for concern.

Critical brain development

Teen marijuana use affects the brain during a critical point of development. This window of time is when the brain still has flexibility and continues to build important connections. The brain has many opportunities to grow and mature, but it is also vulnerable.

The brain settles into its adult state when a person gets into their mid-20s. Any major changes during this final stage of development can have long-lasting effects. Occasional use may not have a strong impact. But frequent use at a young age may disrupt this critical phase.

Research has shown that adolescents using heavy amounts of marijuana lose grey matter in areas of the brain related to memory, learning, and impulse control. Nerve growth factor (NGF) is an essential body chemical at work during the teen years. It’s involved with the growth of nerve connections in the brain. The THC in marijuana suppresses NGF. At lower levels, NGF can’t do its job growing nerve connections.

Over time, the reduced presence of NGF may stunt a person’s emotional and mental maturity. In other words, they may get stuck with an adolescent brain for the rest of their life.

Decline in school performance IQ

Researchers have found connections between heavy marijuana use and a drop in brain functioning. This drop is enough to result in lower IQ scores, similar to lead poisoning. Marijuana also affects a person’s motivation. When it’s hard to get up and go to work or school, a person’s motivation usually kicks in.

Going to school, paying bills, or other ongoing responsibilities can feel like a lot some days. But over time, a person understands what it takes to take action when they don’t feel like it. This can be especially tough for teens. They are naturally more distractible and likely to get swept up by emotional whims. This is why teens can be both fun and frustrating. But it’s also why marijuana use can be so damaging for them.

Trouble with independent living

In adulthood, these academic problems can evolve into other difficulties. Adults who used marijuana heavily as a teen are more likely to have problems in the workforce, a greater reliance on welfare, and lower life satisfaction. With lower motivation than their peers, an adult with these limitations will struggle with independent living.

Increased risk of depression and anxiety

Chronic marijuana use is harmful to the body’s natural stress response. The chemicals in marijuana both dull and exaggerated a person’s emotional reactions. Teens with this issue will have trouble keeping emotions in balance.

A teen who can’t manage emotional ups and downs well may also be at risk for other mental health concerns. Teens going through treatment for heavy marijuana use are also more likely to have depression or anxiety. This combination makes the typical challenges of daily life more difficult.

The effect of marijuana on the brain is different for adults

Adults could recover from the brain-dampening effects by abstaining. These last longer and are more potent for teenagers. Abstinence isn’t enough to counteract the impact. Simply put, every dose is a lot more harmful to teens than it is to an adult. Brains are more sensitive and have more receptors for the THC to bind to.

Potential for dependence

A person who uses marijuana heavily may eventually develop a dependence on it. And research shows that about 1 in 6 teens using marijuana heavily become dependent.

The brain and body adapt when a person uses a substance heavily. The nearly constant presence of the substance becomes normal. And when they stop using, even for a short while, withdrawal symptoms show up. Unfortunately, the easiest way to make withdrawal go away is to start using it again.

Marijuana and the teen brain – the harmful unknown

It’s difficult for experts to fully understand the effects of marijuana on the teen brain from a long-term view. THC levels are much higher today than a few decades ago. Also, everyone has different reactions to marijuana, so these effects need to be studied further.

As research catches up to current trends and data about marijuana use, experts will learn more. But for now, caution is the crucial message for teens and their families.

New Dimensions Can Help!

If you or someone you know is experiencing any of the above symptoms or problems, New Dimensions can help. Our team of experienced therapists and psychiatrists can help you overcome these challenges and help you develop the skills you need to thrive. To schedule a complementary assessment or to find out more about our programs, contact us at 1-800-685-9796.

Our affiliate, MHThrive, provides Individual Therapy, Couples and Marriage Counseling, and Family Therapy at our locations in Katy, The Woodlands, and the Clear Lake area of Houston, Texas. We also provide telehealth therapy for anyone who resides within the State of Texas. To schedule an appointment with one of the MHThrive therapists, contact us at 713-477-0333 or visit to learn more.