Substance Use and Substance Use Disorders

Adolescence is the developmental period in which most substance use begins, ranging from experimentation with alcohol, nicotine, and cannabis to the use of other drugs, and in which substance use disorders may first take hold. Because the adolescent brain is still maturing, early and heavy use is of particular concern for both immediate harms and longer-term addiction risk.

Definition

Substance use disorders are patterns of use of alcohol or other drugs leading to clinically significant impairment or distress, marked by impaired control, continued use despite harm, and physiological features such as tolerance or withdrawal; in adolescents the construct spans a continuum from initial use through disorder.

Scope

This entry covers the spectrum from adolescent substance use to substance use disorders: the substances most commonly involved, the developmental and epidemiological context, and recognized screening frameworks. It is reference-educational and does not provide treatment dosing or individualized clinical advice.

Core questions

• Which substances are most commonly used by adolescents, and at what ages does use typically begin?
• How does ongoing brain development shape vulnerability to substance use and addiction in adolescence?
• How are adolescents screened for substance use, and what frameworks guide brief intervention and referral?

Key concepts

• Continuum from use to substance use disorder
• Early onset and developmental vulnerability
• Brain disease model of addiction
• Alcohol, nicotine, and cannabis as leading substances
• Comorbidity with other mental disorders
• Screening, brief intervention, and referral to treatment (SBIRT)

Mechanisms

Repeated substance exposure acts on brain reward, motivation, and self-control circuitry; the brain-disease model of addiction describes how this produces compulsive use and impaired control. Because adolescent prefrontal and reward systems are still developing, early initiation is associated with greater vulnerability to escalation and to substance use disorders. These mechanisms summarize the dominant neurobiological account in the literature rather than a fixed individual trajectory.

Clinical relevance

Adolescent substance use is associated with injury, comorbid mental disorders, educational and social harms, and increased risk of later substance use disorder. The entry describes recognized screening and referral frameworks as background on how the problem is addressed in practice; it offers no individualized treatment or dosing guidance.

Epidemiology

Initiation of alcohol, nicotine, and cannabis use is concentrated in adolescence, and earlier onset of use is associated with higher risk of developing a substance use disorder. National survey data document substantial prevalence of substance use and substance use disorders among adolescents and young adults, frequently co-occurring with other mental disorders.

History

Understanding of adolescent substance use shifted over the late twentieth and early twenty-first centuries from a primarily moral or behavioral framing toward a developmental and neurobiological one, exemplified by the brain-disease model of addiction. In parallel, structured screening approaches such as SBIRT were developed and recommended for adolescent care settings.

Debates

The brain-disease model of addiction

The framing of addiction as a chronic brain disease has been influential for guiding research and reducing stigma, but it is also debated by those who emphasize social, behavioral, and contextual contributors; the discussion shapes how adolescent substance use is conceptualized.

Key figures

• Nora Volkow
• Bridget Grant
• Sharon Levy
• A. Thomas McLellan

Seminal works

• volkow-2016
• grant-2015
• levy-2016

Frequently asked questions

Why is early substance use a particular concern in adolescents?

Because the adolescent brain is still developing, earlier initiation of substance use is associated with greater risk of escalation and of developing a substance use disorder later.

What is SBIRT?

Screening, Brief Intervention, and Referral to Treatment is a structured framework, recommended for adolescent care settings, for identifying substance use, delivering a brief intervention, and referring those who need further treatment.