Epidemiology and Pathogenesis

Patterns of drug initiation and drug use vary by age, gender, race, ethnicity, and substance availability in an adolescent’s community. Monitoring the Future Study (MTFS) is a nationally representative study that follows trends in adolescent drug use and attitudes. As adolescents mature, they report higher rates of substance use (Figure 82-1). Notably, alcohol is the most commonly reported substance used by adolescents followed by cigarette use and marijuana use. Use of other illicit drugs substances, although less common, poses risks resulting from acute impairments in judgment or long-term addiction. More recent surveys have highlighted the increased availability and recreational use of prescription drugs such as hydrocodone bitartrate (Vicodin), oxycodone (Percocet), and methylphenidate hydrochloride (Ritalin). Although illicit substances can signify an increased risk for an individual adolescent, pediatricians need to routinely discuss alcohol-related issues given that 43% of 12th graders; 29% of 10th graders; and 16% percent of 8th graders reported using alcohol based on 2008 MTFS data. Although adolescents drink less frequently than adults, when consuming alcohol, teens tend to drink more at one time compared with adults. Remarkably, from the same survey, 25% of 12th graders, 16% of 10th graders, and 8% of 8th graders report having consuming five or more drinks on at least one occasion.

Figure 82-1 Thirty-day reported substance use by grade.

Pediatricians will find that a substantial proportion of their adolescent patients will report trying substances, yet of these teens, only a minority will abuse a substance or become physiologically dependent (Figure 82-2). Progression from experimentation to abuse or physiologic dependence results from the complex interplay of numerous biopsychosocial risks and protective factors, including adolescent physical, emotional, and cognitive development, and environmental factors, including peers’ and family’s attitudes and behaviors, genetic predisposition, and mental health stressors.

Figure 82-2 Substance dependence (addiction).

Recent research elucidates how maturation of the prefrontal cortex impacts risks associated with substance use. Initially, the adolescent brain learns to feel intense emotions with limited self-control followed later by the maturation of regulatory systems, which temper these emotions and allow the adolescent to assess immediate and long-term risks. This developmental sequence helps to explain why younger adolescents may experience excessively positive emotions associated with a substance and less moderation of behavior, resulting in risk of immediate harm and long-term dependence. Adolescents who physically mature earlier are at increased risk because they may have the opportunity to socialize with older adolescents and be exposed to a wider variety of substances. Learning what substances are commonly available and used by adolescents in a particular school or community can be extremely helpful in screening for particular substance use. Although availability and social cues from peers are strongly correlated with continued substance use, the highest predictor of long-term substance use or abuse is the adolescent’s family’s substance use patterns. This may be due to ongoing behavioral stimuli or a genetic predisposition; both mechanisms have been implicated in alcohol dependency and nicotine addiction.

Mental health issues and past traumas can increase the risk that an adolescent will begin using substances on a regular basis to elevate mood, dull anxiety, or avoid feelings altogether. Adolescents with depression, anxiety, attention-deficit/hyperactivity disorder, and conduct disorders are at significantly increased risk for using substances to manage symptoms related to these disorders (Figure 82-3). A history of having experienced childhood physical or emotional abuse, past or ongoing family conflict, inadequate parental supervision, isolation from school, poor academic achievement, and sexual or gender identity concerns can increase the risk that an adolescent may begin to use and experience harm from substances.

Figure 82-3 Mood disorders.