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Can we reverse the effects of drugs on developing brains?

These researchers are trying to find out

Lauren Mackenzie Reynolds


McGill University

When I was a kid, there was an anti-drug PSA on TV showing a man holding an egg (this is your brain) and a hot frying pan (this is drugs). He breaks the egg into the pan (this is your brain on drugs). He holds the pan up to the camera as the egg oozes and sizzles.

Any questions?

I had questions. In part, these questions are what formed my path into neuroscience.

I had always felt that those PSAs were heavy handed, too deeply entrenched in the ‘Just Say No’ message. Not everyone who takes drugs recreationally becomes addicted. But as I began to delve into this topic for my PhD thesis, one thing became apparent: the earlier you start using drugs, the more likely you are to become an addict later in life.

This suggests that the strongest strategy to reduce addiction is indeed to stop teenagers from taking drugs in the first place. Since the 1980s, widespread in-school prevention programs based around the concept of 'Just Say No' were launched to achieve this goal. But follow-up studies show that this message is generally unsuccessful at curbing adolescent drug use. 

However, more effective evidence-based prevention programs – featuring interactive sessions that target the psychosocial factors associated with drug use – are increasingly being implemented in schools and communities.

That will likely convince some teens to avoid drugs, but what happens to those teenagers that do take them? Is there any way to intervene to prevent the long term increase in addiction risk associated with their early drug use?

The more that I studied the effects of drugs on adolescent brain development, the more I grew to like the fried egg metaphor used in that anti-drug PSA. Cooking an egg changes the physical structure of its proteins. This change causes the egg to turn from a liquid state into a solid state. Drugs of abuse likewise cause changes to the structural make up of the brain, leading to dysfunction in neurocircuitry important for regulating behavior.

While exposure to drugs at any age can lead to these structural and functional changes in the brain, during adolescence the brain is still under construction. Regions of the brain important for decision making, critical thinking, and behavioral inhibition are developing connections to each other, or pruning back unnecessary connections in order to establish the most appropriate neural pathways to support behaviors necessary for a successful adulthood.

This means that adolescence is a really important time for the nurture aspect of development. Teenage experiences are vital for the development of the brain, so that it knows what kind of environment to expect during adulthood. Drug use during this time can disrupt how the brain circuitry is assembled and lead to changes that promote – rather than protect against – addiction. This means that drugs are structurally changing the adolescent brain, much like cooking an egg structurally changes its protein composition.

Kids these days, amirite?

Erik Charlton

So if scientists have figured out how to uncook an egg, can we 'uncook' the brain of a teenage drug user? To be able to design and implement interventions aimed at reversing, or at least mitigating, the effects of teenage drug use on the brain, we first need to know more about how drugs impact the formation and plasticity of neural circuitry during this time. The focus of my research, and that of other teams, is on discovering how abused drugs change the proteins important for circuitry development in adolescents.

Once we know the mechanisms that drugs use to change the brain, we hope to try to reverse them by using evidence-based treatments to push back, molecularly, against the changes. Our goal is to try to develop easy to implement, non-invasive interventions to restore healthy brain function and help mitigate the long-term risks associated with adolescent drug use. These interventions could be as simple as targeted dietary changes, exercise, and social support, which have all been shown to affect adolescent brain development in animal models.

By combining evidence-based prevention and evidence-based treatment, we hope that future teenagers will be haunted for the rest of their lives by their prom pictures – not their decisions about drug use.