Neurobiology of Cigarette Craving in Adolescent Smokers
Abstracts
Initial Award Abstract |
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In the U.S. there are 430,000 smoking-related deaths each year, making smoking the leading preventable cause of disease and death in our country. Eighty percent of adult smokers become addicted to tobacco by age 18 (American Health Association, 1995), suggesting that adolescents are a very vulnerable age group to the effects of smoking. Adolescent tobacco use increases risk for a wide range of negative health consequences. For example, the earlier in life that smoking begins and the longer time smoking, the greater chance of smoking-related cancer risk in adulthood. This unfortunate fact underscores the importance of addressing this public health concern as early in life as possible. Although numerous brain studies have been conducted on nicotine craving and addiction in adults, no comparable research has been done in adolescent smokers. In fact, adolescents represent a relatively understudied smoking population. In this project, our primary goal is to investiage how nicotine and smoking affects the developing brain. We will address a simple question: Is the adolescent brain more susceptible to nicotine-related cues, craving and smoking than the mature brain? An understanding of how susceptible the adolescent brain is to nicotine and cigarette craving will help determine neurobiological factors that contribute to the initiation and maintenance of cigarette smoking in adolescents. Exposure to nicotine during adolescence might alter brain development in a way that increases the reinforcing properties of nicotine as well as other drugs of abuse. For example, it has been suggested that most adults could be prevented from becoming smokers if they were kept tobacco-free during adolescence. Theories that nicotine can serve as a "gateway" drug suggest that nicotine might have a unique effect in this vulnerable age group. Research supports this view: among middle and high schoolers, the prevalence of alcohol and illicit drug use were 7 and 10 times as high in smokers as in nonsmokers. Aside from effects on the rewarding properties of drugs of abuse, exposure to nicotine during adolescence might affect the core neural systems underlying reward and impulse control behavior. Disruption of the development and functioning of these systems might be involved in the initiation and maintenance of drug dependence. Individuals who receive addiction treatment in the early stages of their addiction are more likely to remain abstinent later in life. Targeting and treating adolescent smokers may therefore be the best way ultimately to reduce nicotine dependence in the general population. Brain imaging offers an opportunity to learn how neural systems change with development. Given the high incidence rates of smoking initiation in the adolescent years, understanding the development of neural systems that are sensitive to smoking cues and craving will elucidate potential targets for prevention and intervention purposes. Work from our lab and others' has shown that the brain undergoes substantial development during adolescence. Neural circuits related to craving, craving suppression, and addiction in adults are those that undergo the most dramatic neurodevelopment in adolescence. This project will use brain scans to determine adolescent brain function when presented with smoking-related pictures, during craving and during craving suppression. An adult comparison group will also be studied. We hypothesize that 1) adolescents will show greater neural activity to smoking-related cues than adults, suggesting greater susceptibility to these cues; 2) that self-reported cigarette craving will be associated with brain activity; and 3) that adolescents who show limited neural activition in regions known to control behavioral inhibition will report greater difficulty in suppressing their cigarette craving. Ultimately, we hope this research will be the foundation for more applied intervention and research aimed at reducing smoking initiation among adolescents and, subsequently, the number of individuals who suffer the long-term consequences of adolecence-initiated smoking. |
