Adolescent Brain Development:
Understanding the Impact of Substance Use

A Congressional Briefing Sponsored by The Friends OF NIDA
In Conjunction with the Congressional Addiction, Treatment and Recovery Caucus

Monday, October 20, 2014

On Oct. 20, 2014, the American Psychological Association (APA) organized a briefing for members of Congress and their staff titled, “Adolescent Brain Development: Understanding the Impact of Substance Use" (PDF, 69KB). The briefing was sponsored jointly by the Friends of the National Institute on Alcohol Abuse and Alcoholism and the Friends of the National Institute on Drug Abuse in cooperation with the Congressional Addiction, Treatment and Recovery Caucus. Thirty organizations, including APA, provided sponsorship and, with over 120 attendees, it is clear that there is tremendous interest in this important topic.

The panel of speakers included George F. Koob, PhD, director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA), Nora D. Volkow, MD, director of the National Institute on Drug Abuse (NIDA) and Sandra Brown, PhD, vice chancellor for research, and distinguished professor of psychology and psychiatry at the University of California, San Diego, and the director of the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA).

The briefing focused on the Adolescent Brain Cognitive Development (ABCD) (PDF, 386KB) study, which is an ambitious project that aims to follow 10,000 adolescents across a 10 year span. By enrolling participants at a young age, before any introduction to substance use, the researchers hope to track the impact of substance use on brain development. There are still many open questions about how the brain develops. Since research has shown that brain development continues into the twenties, it is unclear how substance use among this age group will affect them later in life. One of the goals of the ABCD study is to shed light on this issue.

Koob presented first and provided an overview of developmental research on alcohol misuse (PDF, 4.21MB) and its effects on youth in the U.S. Koob spoke on the changing drinking culture in American students over the last 40 years. The results indicate that since 1975, the frequency of binge drinking, defined as raising blood alcohol concentration level of .08 within two hours, has been on a general decline across American middle and high school students. However, the amount of consumption while drinking has increased dramatically.

Between 1999-2008, the rate of hospitalizations related to alcohol overdoses of 19-24-year-olds increased by 67 percent. While it is common knowledge that binge drinking leads to risky behavior such as drunk driving, unprotected sex and physical injury, scientists are increasingly seeing the long term consequences in brain development. Koob discussed several additional topics including the neurocircuitry of addiction; the societal costs of underage drinking; the effects of alcohol at different developmental stages in the adolescent brain; new initiatives to explore the neurobiological effects of adolescent drinking that persist into adulthood; and a variety of prevention efforts on college campuses including screening and brief interventions specifically tailored for youth.

Adolescence is a period of increased vulnerability to other substances, such as marijuana, which likewise appear to alter brain and cognitive development, as discussed in Volkow’s presentation (PDF, 6.29MB). Volkow highlighted how adolescents are at greater risk for substance abuse because the brain’s reward system is functioning at a heightened level of sensitivity. Therefore, teens and young adults receive a greater reward from substances than older adults, making the substance more reinforcing, effects that appear to be mediated by changes in dopamine neurotransmission during brain maturation. Although Volkow detailed the detrimental effects of adolescent substance use, she also summarized the role of risk and protective factors relevant to the design of effective prevention programs. While early aggressive behavior, poor social skills and lack of parental supervision increase the risk of substance use, enhancing self-control, positive relationships and supportive parenting have been shown to decrease substance abuse in teens.

Brown was the final presenter (PDF, 4.38MB). Brown’s research has focused largely on the implications of adolescent alcohol and drug abuse and treatment. As the director of the NCANDA, Brown has unique insight into the scientific potential of a large scale prospective study like the ABCD. Brown’s data added to a growing body of evidence that suggests adolescent substance use is more harmful than previously thought, particularly with respect to learning and memory.

Brown discussed research that has shown cognitive impairments sustained by substance abusing teens in treatment. Generally, adolescent substance users perform worse on a variety of tests of cognitive function, although treatment for substance use has been shown to be effective in these populations. Nonetheless, the results of brain scans show that early substance use may be rewriting the brain’s normal learning and memory pathways.

For instance, after prolonged abstinence, binge drinkers can obtain an equal level of performance on tests of memory and visuospatial ability. But it appears their brains are functioning in a different way. The volumes of both white and gray matter are diminished and the structural integrity of white matter appears to be more diffuse when compared to normal controls. How these conditions will affect them later in life is unknown.

Given evidence of such dramatic morphological and functional effects on the adolescent brain, the importance of answering critical questions about substance use cannot be overstated. Current technology has reached a point where following such a large group of adolescent participants for ten years is feasible. What is unclear is whether policymakers will deem the ABCD study worthy of the long-term funding that such a study requires. APA will continue to advocate for sustained research funding in this area.

Pictures from the briefing:

Koob, Volkow, and Brown

(left to right) Koob during his presentation on alcohol misuse; Volkow of NIDA during her talk "Adolescent Brain Development: Understanding the Impact of Substance Abuse"; Brown presenting "Adolescent Brain Development: Understanding the Impact of Substance Use."
Volkow, Koob and Brown.

Left to right: Volkow, Koob and Brown.