Boileau et al, Modeling Sensitization to Stimulants in Humans:
An [11C] Raclopride/Positron Emission Tomography Study in Healthy Men
Arch Gen Psychiatry
How much of an impact do psychoactive drugs have on our lives and those of our loved ones? Drug use today is very popular, especially among young people. With 47% of high school students having experimented with marijuana (Centers for Disease Control and Prevention, 1999) and 21.5% of 18-25 year-olds currently using illicit drugs (Substance Abuse and Mental Health Services Administration, 2010) it wouldn’t be a stretch to assume that most Americans have either tried drugs at one point or have a friend, family member, or acquaintance who has. Many of these people believe that their drug use will be temporary and that, after they stop, life will continue for them as it was before. However, Dr. Isabelle Boileau and her team of researchers at McGill University have found evidence suggesting that after just one dose of a drug such as amphetamine, a substance that college students may know as Adderall, the brain changes in significant, long-lasting ways.
Studies in animals have shown that repeated exposure to stimulant drugs causes increases in behavioral responses to the drug and in the release of dopamine, a chemical messenger in the brain that codes for wanting. This process, called sensitization, has been well documented in animals, but not much research has been done to investigate whether this effect occurs in humans. Boileau and her team attempted to do just that.
In her study, ten young men were given three small doses of amphetamine over the course of a week, a fourth dose two weeks later, and a fifth dose after a year. The researchers measured brain activity before initial amphetamine administration and after administrations of the first, fourth, and fifth doses to see if there were any changes.
Interestingly, participants responded much more strongly to the fourth amphetamine dose than they did to the first one, even though they received it after a two-week drug-free period. They exhibited increased energy, alertness, clear-headedness, positive mood, and eye-blink rate. Furthermore, the dopamine released in their brains increased in both volume and area, expanding to more brain regions. The most fascinating thing that they found, though, was that, compared to the brain response after the first amphetamine dose, dopamine transmission was enhanced after administration of a fifth dose given an entire year after being drug-free. In other words, a year after participants stopped taking amphetamine, their brains had still not returned to normal!
This suggests that repeated administration of amphetamine, even infrequently and in small doses, changes the brain in significant, long-lasting ways. Specifically, the brain is sensitized to the drug and responds more strongly to it with each dose, a phenomenon which Boileau believes may confer vulnerability to addiction.
These findings give us all reason to take pause. If the brain’s response to amphetamine is enhanced with repeated use and this phenomenon increases the likelihood of addiction, then what will become of today’s college students who seem to take Adderall as if it were Advil? Furthermore, if amphetamine has long-lasting, snowballing effects on the brain, can we assume the same about more commonly used substances like marijuana and alcohol?
I would like to acknowledge Elizabeth Shackney, one of the writing tutor who works for the writing workshop. She was the first person to read my press release. I would also like to acknowledge my Motivation and Reward professor, Mike Robinson, for the wonderful advice and guidance he gave me. I wish to acknowledge my classmate, Jonah Toussaint. He was the final person to read and edit the first submitted version of my press release. The feedback from each of these people helped make my press release what it is now. Finally, I wish to acknowledge Liana Mathias for reading the second version of my press release and suggesting wording and syntactical changes that really helped add clarity to it.
- Added more information about the study to make it more understandable to lay people and made more connections between drugs and college students.
- Made big stylistic changes. Made the methods and results sections more story-like as opposed to restating facts. Changed the intro to make the theme more relatable to everyone as opposed to just people who have used drugs.
- Shortened the press release by about 50 words to meet word limit.
- Changed the wording and sentence structure to make the paper more clear.
Boileau, I., Dagher, A., Leyton, M., Gunn, R. N., Baker, G. B., Diksic, M., & Benkelfat, C. (2006). Modeling sensitization to stimulants in humans – An [C-11] raclopride/positron emission tomography study in healthy men. Archives of General Psychiatry, 63(12), 1386-1395. doi: DOI 10.1001/archpsyc.63.12.1386
Centers for Disease Control and Prevention. (1999). Youth Risk Behavior Surveillance System.
Substance Abuse and Mental Health Services Administration. (2010). National Survey on Drug Use and Health.