# Adolescent Substance Use: Screening and Intervention

## Introduction

Substance use typically begins during adolescence, with the developing adolescent brain being particularly vulnerable to the neurotoxic and addictive properties of drugs and alcohol. Approximately 50% of adolescents have tried an illicit substance by 12th grade, and 60% have consumed alcohol. The adolescent prefrontal cortex, responsible for impulse control, judgment, and decision-making, is not fully mature until age 25, creating a biological window of heightened susceptibility. Early screening and brief intervention by pediatricians can delay initiation, reduce use, and prevent progression to substance use disorders.

## Epidemiology and Trends

Alcohol remains the most commonly used substance, with binge drinking peaking in late adolescence. Cannabis is the second most common, and increasing THC potency in modern products is concerning, as adolescent use is linked to psychosis risk, cognitive impairment, and lower educational attainment. Vaping and e-cigarettes have reached epidemic levels among youth; these nicotine delivery devices are often mistaken as harmless, flavored products increase appeal, and EVALI (e-cigarette or vaping product use-associated lung injury) has been linked to vitamin E acetate in THC cartridges. Nicotine is highly addictive, and adolescent brains develop dependence more rapidly than adults, with vaping serving as the primary nicotine delivery method in youth. Prescription drug misuse includes opioids, stimulants (diverted ADHD medications), and benzodiazepines. The opioid crisis has been compounded by fentanyl contamination of illicit drugs, dramatically increasing overdose deaths in adolescents. Other substances of concern include inhalants (particularly among younger adolescents), synthetic cannabinoids, MDMA, hallucinogens, and nitrous oxide.

## Neurobiology of Adolescent Substance Use

The mesolimbic dopamine reward pathway (ventral tegmental area to nucleus accumbens) is hyperactive during adolescence, driving reward-seeking behavior. Meanwhile, the prefrontal cortex responsible for executive function and impulse control is still developing, creating an imbalance between reward drive and behavioral regulation. Adolescent neuroplasticity makes the brain more susceptible to substance-induced changes in synaptic plasticity, increasing addiction vulnerability. Early onset of substance use before age 15 is associated with a 4-fold increase in lifetime risk of substance use disorder. Cannabis use during adolescence may impair hippocampal development, affecting learning and memory.

<image>Diagram of the adolescent brain showing the dopamine reward pathway (VTA to nucleus accumbens) and the relatively immature prefrontal cortex, illustrating how this developmental imbalance creates vulnerability to substance use and addiction</image>

## Screening

### Universal Screening Recommendation

The AAP recommends universal substance use screening at every well visit starting at age 11. Screening should be conducted annually using validated tools, more frequently in high-risk populations, and always in a confidential setting with the adolescent alone and without the parent present.

### Screening Tools

| Tool | Target Age | Format | Scoring | Interpretation |
|------|-----------|--------|---------|---------------|
| CRAFFT 2.1 | 12-21 years | 6 yes/no questions (Part B) | 0-6 points | ≥2: problematic use; further assessment needed |
| S2BI | 12-17 years | Frequency-based (past year) | Categorical | No use / Lower risk / Higher risk / Severe disorder |
| AUDIT | 14+ years | 10 items, alcohol-specific | 0-40 points | ≥8: hazardous use; ≥20: possible dependence |
| NIDA Quick Screen | Adolescents/adults | Single question per substance | Categorical | Any past-year use triggers ASSIST follow-up |

The CRAFFT 2.1 is the most widely used validated tool in pediatrics. Part A asks whether the adolescent drank any alcohol (more than a few sips), used any marijuana, or used anything else to get high during the past 12 months. If any answer is "yes," Part B poses six questions: whether they have ridden in a Car driven by someone who was high or had been using alcohol or drugs; whether they use alcohol or drugs to Relax, feel better about themselves, or fit in; whether they use while Alone; whether they Forget things done while using; whether Family or Friends tell them to cut down; and whether they have gotten into Trouble while using. Each "yes" scores 1 point, and a score of 2 or greater indicates problematic use requiring further assessment.

The S2BI (Screening to Brief Intervention) is a frequency-based tool that asks about past-year frequency of tobacco, alcohol, marijuana, and other drug use and categorizes risk level as no use, lower risk, higher risk, or highest risk/severe disorder. The AUDIT (Alcohol Use Disorders Identification Test) is a 10-item tool for alcohol-specific screening.

### Risk Assessment After Positive Screen

After a positive screen, the clinician should determine frequency, quantity, and context of use and assess for DSM-5 substance use disorder criteria (mild: 2-3 symptoms; moderate: 4-5; severe: 6 or more). Evaluation for co-occurring disorders is essential, including depression, anxiety, ADHD, trauma/PTSD, and eating disorders. Functional impairment should be assessed across domains including academic decline, relationship problems, legal issues, and risky behaviors while intoxicated. Safety assessment should address driving under the influence, concurrent use of multiple substances, and suicidal ideation.

## Brief Intervention (SBIRT Model)

### Screening, Brief Intervention, and Referral to Treatment (SBIRT)

For adolescents reporting no use, the clinician should provide positive reinforcement of healthy choices and anticipatory guidance about peer pressure and risks. For occasional or experimental use, a brief motivational intervention of 5-15 minutes is appropriate, involving expression of concern using nonjudgmental language, clear medical advice about health risks, motivational interviewing techniques (open-ended questions, affirmations, reflective listening, summarizing -- known as OARS), assessment of readiness to change using the stages of change model, and setting a collaborative goal such as reducing use or avoiding driving impaired. For problematic use or substance use disorder, brief intervention should be combined with referral to specialized treatment, which may include outpatient counseling, intensive outpatient programs (IOP), or residential treatment depending on severity. Medication-assisted treatment (MAT) should be considered for opioid or alcohol use disorder.

<image>SBIRT (Screening, Brief Intervention, and Referral to Treatment) flowchart showing the pathway from universal screening through risk stratification (no use, low risk, high risk, severe disorder) to appropriate interventions at each level, including brief motivational intervention techniques and referral criteria</image>

## Specific Substance Considerations

### Vaping/E-cigarettes

E-cigarettes contain nicotine (highly addictive), flavoring chemicals (diacetyl, which carries a risk of bronchiolitis obliterans), heavy metals, and ultrafine particles. Adolescents who vape are 4 times more likely to initiate combustible cigarette smoking. For cessation, behavioral counseling is first-line, and nicotine replacement therapy (NRT) may be considered for heavily dependent adolescents, though it is off-label under 18 in most settings.

### Cannabis

THC concentration in modern products is significantly higher than in prior decades, averaging 15-20% compared to 3-4% in the 1990s, with concentrates exceeding 80%. Health risks in adolescents include impaired memory and learning, decreased motivation, increased risk of psychosis (especially with early onset and heavy use), and cannabinoid hyperemesis syndrome. "Medical marijuana" lacks pediatric evidence for most conditions.

### Opioids

Fentanyl contamination of illicit drugs, including counterfeit pills and heroin, is the leading driver of adolescent overdose death. Naloxone (Narcan) should be prescribed to any adolescent at risk for opioid exposure, is available over-the-counter, and families should be educated on its use. For medication-assisted treatment of opioid use disorder in adolescents, buprenorphine is first-line (FDA approved for age 16 and older), and naltrexone (extended-release injectable) is an alternative.

### Alcohol

Binge drinking (4 or more drinks for females, 5 or more for males in 2 hours) carries acute risks including aspiration, alcohol poisoning, sexual assault, and injury. For alcohol use disorder in adolescents, naltrexone or acamprosate may be considered, though pediatric data are limited.

<image>Visual comparison of common substances used by adolescents (alcohol, cannabis, nicotine/vaping, opioids, stimulants) showing health effects specific to the developing adolescent brain, signs of use that clinicians should recognize, and evidence-based intervention strategies for each</image>

## Clinical Pearls

All adolescents should be screened for substance use annually starting at age 11, as universal screening is more effective and less stigmatizing than risk-based screening. A CRAFFT score of 2 or greater warrants further assessment, but even a score of 1 (especially for the "Car" question) warrants brief intervention about safety. Motivational interviewing is more effective than confrontation or scare tactics, and clinicians should meet the adolescent where they are. Naloxone should be prescribed to any adolescent at risk for opioid exposure, as fentanyl contamination makes any illicit drug use potentially lethal. Substance use rarely occurs in isolation, so clinicians should always screen for co-occurring mental health conditions including depression, anxiety, PTSD, and ADHD.

## References

1. Levy SJ, Williams JF, Committee on Substance Use and Prevention. Substance Use Screening, Brief Intervention, and Referral to Treatment. *Pediatrics*. 2016;138(1):e20161211.
2. Knight JR, Sherritt L, Shrier LA, et al. Validity of the CRAFFT Substance Abuse Screening Test Among Adolescent Clinic Patients. *Arch Pediatr Adolesc Med*. 2002;156(6):607-614.
3. Volkow ND, Swanson JM, Evins AE, et al. Effects of Cannabis Use on Human Behavior, Including Cognition, Motivation, and Psychosis. *JAMA Psychiatry*. 2016;73(3):292-297.
4. Hammond CJ, Mayes LC, Potenza MN. Neurobiology of Adolescent Substance Use and Addictive Behaviors: Treatment Implications. *Adolesc Med State Art Rev*. 2014;25(1):15-32.