How drugs affect the teenage brain

Before reading this, please refer to the previous blog post to understand the brain terms we will be using, and how drugs affect the brain in general. 

There are two important ways in which the teenage brain is uniquely sensitive to and affected by drug use. 

1) During adolescence, the midbrain (the area responsible for reward and motivation, which is profoundly influenced by certain drugs) is well developed, but the prefrontal cortex (the rational part of the brain) is the last area of the brain to develop. As a result, pleasure and emotion—not reasoning—guide most teen behavior.This means teens are more prone than adults to engage in risk-taking behaviors. Their impulses are very powerful, while their ability to control those impulses is not quite as strong.

2) Drugs have an increased impact on the teenage brain, as compared to adults. During adolescence the brain is developing at a rapid rate. Excess grey matter is pruned out, making brain connections more specialized and efficient, which results in a more skilled and well functioning brain. This pruning process is changed by persistent substance use. fMRI machines show altered grey and white matter in the brains of adolescents using substances.

How does this affect the adolescent? Research has shown that certain substances used persistently in adolescence result in a decline in cognitive ability: impaired problem solving; arrested emotional development; difficulty with memory recall; disruptive, chronic, and persistent lack of motivation; increased risk of mental health disorders (other than addiction), including mood disorders, anxiety disorders, and psychotic disorders.

According to research, the earlier an adolescent began using substances, the higher the risk of developing a substance use disorder. Cognitive decline related to substance use is worse for people who started before 18 years old. These cognitive changes persisted even when the adolescent did not use for at least a year

If you are a parent…. DON’T PANIC!

These studies were done on teens with persistent, chronic substance use. The effects of drug use are mitigated by environment, extent of use, and other predisposing factors. Most of us experimented with drugs in our teens, and most of us turned out okay. Not only that, but rates of teen drug use have dropped since the 90s! (Internet addiction has gone up, but that’s a blog post for later….)

Share information rather than just rules

Teach your teens about the critical period they are in with respect to their brain development, how this could impact their response to peer pressure and risky situations, and how this makes their brain more vulnerable to the negative long term effects of substances if used persistently. Encourage them to delay substance use as long as possible to reduce their risk of substance use disorders and cognitive deficiencies. Teach them about healthy ways of reducing and coping with stress and peer pressure.

Pay attention to how you lead by example: if you tell your teen to practice healthier ways of coping with stress but then they see you go straight for a glass of wine after a rough day at work…

Well, you see where this is going.

If you are concerned that your teenager may have a problem with substance use already, share your concerns in a calm, open-minded way, and invite them to share any questions or concerns with you. Try to arrange an evaluation by their doctor, who can help determine the extent of the problem and direct you to helpful resources.

Most importantly, when speaking with your teens, keep the conversation neutral and nonjudgemental. Adolescent are curious, and curiosity is important for their developing brain. Share information, rather than just rules, with them. This will help them better understand themselves and their environment, and exercise appropriate caution and sensibility as they develop their independence and explore their world.

Addiction 101: How drugs affect the brain

Before we can discuss what drugs do to the brain, we first need to know a few basics about how the brain works.

While the brain is an exquisitely complex organ, it can be simplified in to 3 main parts: the hindbrain, the midbrain, and the forebrain. They evolved in that order,  and develop in that order as we progress from fetus to adult. 3897464

The hindbrain is the most ancient, primitive part of the brain. It is responsible for respiration, circulation, and digestion; critical life functions which require no conscious effort on our part. Heck, even fish have hindbrains. 

The midbrain receives and integrates sensory information, and directs motor activity. The midbrain is involved in pleasure, reward, and motivation. When we do something pleasurable, this part of brain gets rewarded by a rush of dopamine. This makes us feel good, and motivates our behavior to do more of whatever it was that caused it to be released. Dopamine is the chemical that gets released when we eat/have sex /bond with the clan, activities important for our survival. 

The forebrain is the executive. It includes the prefrontal cortex, which continues to develop through adolescence and is only fully mature in adults. It is responsible for higher level functions – decision making, problem solving, strategizing. When someone tells you to be reasonable or use your head, they are talking to your prefrontal cortex. 

Usually the midbrain and forebrain work in concert. The midbrain might take in an image of a handsome guy, get a dopamine rush, and say, wow, he is super sexy and I would like to hook up with that man. The prefrontal cortex would then say, “Ahem, you are married”. The forebrain has our best interests at heart, though our midbrain may not agree. A well-developed forebrain can overpower our midbrain to determine our behaviors, but it cannot control our desires. You can avoid cookies as much as you want, but you are not likely to ever crave celery. 

So how do drugs affect the brain? 

Addictive drugs increase the number of reward-related chemicals in the brain, one of which is dopamine – the pleasure molecule. Whereas eating a good meal might give our midbrain a squirt of dopamine, certain drugs act more like a firehose. This chemical flood can result in feelings of euphoria, relaxation, and relief from stress. 

When drugs unnaturally increase dopamine in the brain (the chemical that normally gets released when we eat/have sex/bond with our clan) the user gets the message, “you don’t need food or sleep or friendships as much as you need this drug.” That is what causes some drug users to prioritize drug use over even their health and loved ones.

But then they develop tolerance: the amount they used to use no longer causes a release of dopamine. And in the meantime, in response to all the flooding from drug use, their brain has reduced its own dopamine production and sensitivity.

Screen Shot 2019-04-07 at 10.38.11 AMFowler JS, Volkow ND, Kassed CA, Chang L. Imaging the addicted human brain. Sci Pract Perspect. 2007;3(2):4–16.

When they don’t consume progressively higher amounts of the drug, or when they stop using, this neurochemical deficiency precipitates withdrawal. And the symptoms of withdrawal – pain, terrible anxiety, vomiting, diarrhea, sweats and so on – reinforce the midbrain’s false belief that they need the drug in order to survive.

You can appeal the their reason, but remember, reason comes from our prefrontal cortex. Unfortunately, as if the changes noted above were not enough, chronic substance abuse is also associated with forebrain brain impairments, which reduces the user’s ability to regulate their behavior. When a person has a substance use disorder, the midbrain becomes the boss. 

So does that mean it is hopeless? That our friend/family member with substance use disorder is forever lost to their addiction? 

No. Our brain is powerful, but we are not powerless to affect it.

It’s a helluva lot of work, but we can rewire the pathways in our brain through prologued and repetitive practice of new behaviors.

Screen Shot 2019-04-07 at 12.52.29 PM

However, even when people manage to rewire their brain and recover from their substance use disorder, they are at high risk of relapse. You know how a catchy song that you have not heard for over a decade can come on the radio, and suddenly you are belting along to every word? The brain can change so that new pathways predominate, and new behaviors ensue, but the old pathways are still there, dormant, and a single trigger can reawaken them. People with severe substance use disorder typically need to remain vigilant of triggers for the rest of their lives. 

Understanding the brain science behind addiction is important for eliminating the stigma associated with substance use disorder, particularly the assumption that people with this illness are bad/ weak/ making poor choices. Once affected, these people have no more choice in the matter than someone with diabetes does to make their pancreas start producing insulin properly again, or someone with kidney failure does to get off dialysis. Their brain is unwell, and they need compassion, support, and medical care. 

It’s Complicated (Medical complications and how to avoid them)


Someone dear to me is currently in hospital due to a serious complication of what was supposed to be a relatively straightforward elective procedure.

Too often, risk is a quick conversation as pen hovers over consent form. Even when given the time it deserves, studies show that both doctors and patients tend to underestimate the harm and overestimate the benefits, not just of procedures, but also of common tests, and drugs.

For the majority of people, hospital care is safe, but according to a 2016 study by the Canadian Patient Safety Institute, 1 out of every 18 hospitalizations in Canada in 2014–2015 involved at least 1 occurrence of harm. 1 in 8 hospitalizations with a harmful event ends in death (compared to 1/32 who would have died even without a medical complication/error).

Analyzing medical death rate data over an eight-year period, Johns Hopkins patient safety experts have calculated that more than 250,000 deaths per year are due to medical error in the United States. Their figure indicates that medical error is the third leading cause of death in the U.S..

At first glance, this statistic seems improbable. However, complications beget complications. A nick in an artery during a routine procedure may lead to a blood vessel dissection and clot, which, in order to prevent a pulmonary embolism, may require anticoagulation, which increases one’s risk of significant bleeding, and so on.

My cousin died in his early twenties, due to an uncontrollable hemorrhage during an elective tonsillectomy. Not only were his family and friends devastated, his surgeon was so affected that she had to take time off from practicing medicine.pexels-photo-263337

Professor Hoffman, from Bond’s Centre for Research in Evidence-Based Practice, says that doctors’ inaccurate expectations of benefit and risk may be driven by “therapeutic optimism”, underpinned by a desire to help. It can also come from losing touch with latest evidence, pressure from patients, or financial incentives.

The culture of blaming and shaming that persists in many hospitals makes it difficult to address this issue. When my friend’s husband had surgery for a complex ruptured appendix, he was, she said, the star of the ward. The surgeon loved bringing students around to see him. When, two weeks later, her husband was readmitted for a bad post-op infection, they noticed that the surgeon never brought students around anymore. “But wouldn’t that have been the great learning opportunity,” my friend asked, “seeing what could go wrong and how to manage that?”

The good news is that the death rate from complications of medical and surgical care in adults has been declining over the past decade. The tradition of blaming and shaming those involved in a safety incident is being replaced with a culture of openness and learning. Health care leaders have come to understand the importance of focusing of safety and quality improvement. But there is still a long way to go.

Here are some things patients and doctors can do to continue to minimize risk:


  • Ask if your procedure is absolutely necessary, and if not, whether the hoped-for results will have an extraordinary enough impact on your life to assume the risks involved. If not, stop here.

If you must proceed…

  • Ask questions about the procedure and the potential risks.
  • Ask how your doctor will be communicating with or supervising any student learners involved in your care.
  • Determine what the follow up will be after the procedure.
  • Have a family member/friend with you as often as possible while in the hospital.


  • Communicate clearly and gain informed consent. This may mean taking extra time, or obtaining a translator. Ask the patient to repeat the risks back to you.
  • Stay up to date on standards of care. Procedures that used to be common practice may now be deemed unnecessary in many patients, such as cardiac stents or arthroscopy.
  • Remember that your trainees are often sleep deprived and overworked, and need your close supervision. In the end, if something goes wrong, it is you who will be considered at fault, so this is in both of your interests.
  • Share your medical errors/ complications with your students. We all make them, and there is no better learning opportunity.


“Do as much as possible for the patient, and as little as possible to the patient.”



A doctor’s measure of success

After an afternoon of being harassed by angry patients at our inner-city clinic, my exhausted resident (doctor-in-training) asked me how I define a successful day. A simple but critical question. In it lies the key to maintaining our sanity and joy as physicians.

There was a time when I measured my success by how my patients did. After all, if I was a good doctor, they should do well. Right?

I knew of a successful young surgeon – the star of her class. She got a top job at a top hospital. She went to work one day, and scrubbed in for an elective tonsil removal on a 25 year old man. Something went horribly wrong during the surgery. Her patient began to bleed uncontrollably, and she was unable to stop it. He died. His community was devastated. Her colleagues reassured her that it was not her fault, no one doubted that she had done everything possible. But she could not recover from the sense of responsibility and failure. She stopped practicing medicine for years.

Much as we like to believe that our contribution is important, how our patients “do” is not solely the result of our skill as a doctor.  Our patients’ outcomes are affected as much, if not more, by their own motivations, habits, choices, environments, thoughts, and by chance. We are but a tool in their box. Measuring success by how they do will be an emotional roller coaster over which you have no control. Worse still, you may begin to resent their “failures”, which will impact the therapeutic alliance you have with them, and will sap the joy out of your work.

Nowadays, I told my resident, having learned through a healthy dose of error, I measure a successful day by whether I have been my best, most present self for my patients. This is something that I do have control over. I take seriously, and am unapologetic about my self-care. Being present and grounded means I can listen better, and maximize my clinical acumen and skills.

If I measure success by whether I have been my best self, both me and my patients win.

How do you measure a successful work day?