The National Institute of Health is preparing to fund the largest study of adolescent brain development to date. It is called the Adolescent Brain and Cognitive Development (ABCD) Study. This study will spend $150 million (yes, you read that correctly!) to follow 10,000 children ages 9-10 over the course of 10 years. Each year, these kids will be asked a series of questionnaires and put in a functional Magnetic Resonance Imaging (fMRI) scanner to examine how biology and environment interact with each other to impact substance using behavior. Having a better understanding of this information will allow researchers to understand how the brain changes before and after a teen starts using substances.
It is undeniable that a lot of time and money is at stake for these questions to be answered. It will also be a while until any major findings come from this study. And it will be even longer before any policies are implemented as a result. So what do we know about the brain and substance use so far that led the government to spend $150 million?
We currently know that teens who use substances show neurobiological abnormalities. These abnormalities can be seen in brain volume as well as performance on tasks that test memory and attention (Squeglia et al., 2009). The specific changes one experiences depend on the specific substance used. In particular, heavy drinking is related to poorer performance on tasks that test memory, attention, and executive functioning, which is related to planning and organization. Conversely, marijuana use is related to decreases in learning and sequencing scores when given a series of numbers and letters to put in order.
While these results are interesting, we are still severely limited in our understanding of the brain. Many studies previously done on adolescent brain development are brief and don’t show how a teen’s brain changes over long periods of time. Without brain scans being done across several years, it is difficult to know whether substance use impacted brain development or whether there were already differences in the brain that made one more susceptible to substance use in the first place.
One current effort to build on these limitations is called NCANDA, the National Consortium on Alcohol and Neurodevelopment in Adolescence. NCANDA aims to determine the effects of heavy alcohol use on adolescent brain development. To do so, researchers recruited over 800 adolescents and young adults, ages 12-21, across 5 cities in the United States. Each teen went through three annual fMRI scans as well as a number of neurocognitive tests and substance use questionnaires. Although this study does not follow the same individuals from 12 to 21, researchers can stitch together the different trajectories from each adolescent to test the impact of substance use on adolescent brain development.
Some findings have already been released showing that teens with more drinking experience had slower reaction times on multiple tasks compared to those who did not drink or drank low amounts (Sullivan et al., 2016). What is particularly notable about this is that the authors found that the slower reaction times in the excessive drinking group were relatively similar to younger teens whose brains have yet to fully develop. Additionally, teens who reported drinking excessively often responded to cognitive tasks very quickly and very inaccurately.article continues after advertisement
Although these findings seem grim, there is hope.
One study of adult methamphetamine users discovered that after a 12-17 month period of abstinence, there were significant increases in dopamine transporters in the brain (Volkow et al., 2001). This also translated to increases on neurocognitive tests. Although these increases on neuropsychological tests were not statistically significant, it is most likely due to the fact that there were only 5 people in the study and more people are needed to really test for differences.
The low sample size in this study and similar studies along with the lack of longitudinal provide several limitations. It is for these reasons that studies like ABCD and NCANDA are needed to test for brain differences pre- and post- substance use in a large sample.
The limitations in the research so far (e.g., small sample size and short duration) leads us back to the ABCD project. Although the goal of ABCD, which is to understand adolescent brain development, is not new in and of itself, the methods used to answer this research idea are novel. The ABCD project is a 10-year longitudinal study, twice as long as any other study funded by the National Institute on Health (NIH) grant. The ABCD project also includes 10,000 people, more than any other fMRI study done to date. These numbers represent the seriousness and effort the government wants to put into understanding and stopping the substance use epidemic in adolescence.
However, you may be wondering if that $150 million price tag is really worth the effort to understand brain changes in adolescence. Do we really need to spend that much money?
Unfortunately the answer is YES. There are 40 million youth in America, ages 10-19, and an estimated 11% of those have a substance use problem. That means that about 4,400,000 teens are in need of substance use treatment. On top of that, it costs about $10,000 to treat a teen with a substance use disorder and that cost can go up to $30,000 if the teen has another mental health disorder (King et al., 2000). Based off of that, let’s use the $10,000 treatment cost to estimate the total cost adolescent substance use problems has on society:
4,400,000 teens x $10,000 treatment cost = $44,000,000,000
That’s right, $44 billion (yes, billion!) will be spent to treat this pervasive issue. Factor in, vehicle accidents, prison, lost work time, familial costs, emotional distress, and that cost will go even higher. So when we talk about spending $150 million of our hard earned tax money on these kinds of studies, it is a small price to pay to see our children’s’ brains recover.article continues after advertisement
Squeglia, L. M., Jacobus, J., & Tapert, S. F. (2009). The influence of substance use on adolescent brain development. Clinical EEG and neuroscience, 40(1), 31-38.
Sullivan, E. V., Brumback, T., Tapert, S. F., Fama, R., Prouty, D., Brown, S. A., … & De Bellis, M. D. (2016). Cognitive, emotion control, and motor performance of adolescents in the NCANDA study: Contributions from alcohol consumption, age, sex, ethnicity, and family history of addiction. Neuropsychology, 30(4), 449.article continues after advertisement
Verdejo-García, A., Lawrence, A. J., & Clark, L. (2008). Impulsivity as a vulnerability marker for substance-use disorders: review of findings from high-risk research, problem gamblers and genetic association studies. Neuroscience & Biobehavioral Reviews, 32(4), 777-810.Ver
Volkow, N. D., Chang, L., Wang, G. J., Fowler, J. S., Franceschi, D., Sedler, M., … & Logan, J. (2001). Loss of dopamine transporters in methamphetamine abusers recovers with protracted abstinence. The Journal of neuroscience, 21(23), 9414-9418.