The tragic story of Garrett Brown, told by BDN Maine’s Erin Rhoda, highlights a major point that medical professionals have long known: that addiction is a chronic disease. But it also emphasizes another relevant aspect of addiction — the age at which people start using drugs can have a lasting negative impact on the brain’s development. 

Garrett started using marijuana at the age of 10, which later escalated to harder drugs. There is clear medical evidence that adolescent drug users have a higher risk of developing addictions as adults. That’s because the human brain continues to develop until we are in our 20s, and drug use during adolescence can adversely affect this neurodevelopment.

This GIF shows the development of the human brain from the age of 5 to 20.  The lighter colors indicate undeveloped areas.

Data come from National Academy of Sciences©: “Dynamic mapping of human cortical development during childhood through early adulthood.”

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Imagine you’re building your dream home. You’ve invested your life savings; you get one shot. But now that the house is almost complete, a powerful storm comes through and soaks everything. Water, ice and mud are in every nook and cranny, inside the electrical system, in the plywood and framing. You can’t start from scratch, so you clean up as best you can and finish the house. It looks fine from the outside. But you know that storm has caused damage. Had the storm come through after the home was finished, it probably would have done less damage.

The brain’s development is similar to the process of building a home. Our brains rapidly change until we are in our 20s, and much of the critical neurodevelopment that controls our behavior and emotions occur after birth. During adolescence in particular (ages 10-19), the regions of the brain that control emotion, cognition, decision making and impulse control mature.

Adolescents who flood their brains with chemicals do lasting damage at a very critical age of neurodevelopment. These drugs are powerful neuromodulators that modify the function of brain circuits. These changes take root even after the drugs themselves are cleared from the body. They can manifest themselves later in adulthood as a host of emotional problems, like those apparent in the case of Garrett.

The effect of early drug use is well documented in humans and animal models. Of kids who drink by age 14, 15.2 percent become alcoholics, compared with 2.1 percent of those who start drinking after the age of 21. Twenty-five percent of kids who misuse prescription drugs by age 13 will develop substance use problems, compared with 7 percent of those who start after 21. Similar data exist for marijuana and nicotine, and the data can be replicated in controlled studies with animals. Scientifically, it is clear that adolescent drug use is much more harmful, with long-term effects, than it is for adults.

The BDN published a list of 5 lessons that can be learned from Garrett’s case. I would add one more item to this list: engaging our youth at an early age to preempt addiction before it even starts. In a survey of U.S. high school students graduating in 2015, 70 percent had tried alcohol; 40 percent had smoked a cigarette; 50 percent tried illicit drugs, like marijuana, cocaine and methamphetamine; while 20 percent used prescription drugs for non-medical reasons.

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As the parent of an 11-year-old girl, I know that there’s a good chance she will be exposed to addictive drugs during her life. But if that exposure happens after the age of 21 — when the brain is fully developed — she is less likely to develop a chronic disease like addiction. That’s why protecting our youth by preventing drug use during adolescence must be a priority in our fight against addiction.

Vivek Kumar is an assistant professor at The Jackson Laboratory who studies the genetics of addiction. He can be reached at @vivekdna on Twitter.