Stephanie N. Crewe and Arik V. Marcell
Substance use and abuse in adolescence is a major public health problem. Identification of adolescents at risk or those currently abusing substances in the health care setting is often missed, or the substance abuse undertreated. Although the prevalence for substance use over the past decade has decreased from higher rates in the late 1970s, the 2007 lifetime prevalence rates of alcohol use and cigarette smoking among adolescents remain high at 72.2% and 46.2% respectively.1,2 Lifelong substance use habits are formed during adolescence and young adulthood and are associated with short-term and long-term health consequences.
Substance use begins in adolescence or earlier. Among 8th-grade students, the peak years for smoking initiation are between 11 and 13 years of age.1 The average age of first use of alcohol is 14 years,3 and first marijuana use is 16.1 years.4 The most common drugs of use and abuse include alcohol, nicotine, and marijuana. Other substances are drugs used as part of the nightclub/bar and trance scenes, such as ecstasy, rohypnol, γ-hydroxybutyrate, and ketamine. Substances also include over-the-counter drugs, such as sleeping aids, cough and cold medicines and inhalants; and prescription medications, such as pain relievers, amphetamines, and stimulants.
There is no pathognomonic clinical presentation of drug abuse. Signs of drug abuse in an adolescent may manifest in an increasing degree of emotional and physical isolation from the rest of the family, absent or hostile communication, deteriorating school attendance/performance, decrease in athletic performance, a change in peer group, crime involvement, and unplanned/unsafe sexual practices. Known risk factors for the development of substance abuse and dependence are multifold and include male gender, household member drug abuse (eg, by parents), use by peers, earlier age of onset, cognitive disability, and psychiatric comorbidities such as attention deficit hyper-activity disorder and depression.
COMMON SUBSTANCES OF ABUSE
Table 71-1 provides a summary of common substances; examples of commercial and street drug names; route of administration; onset of action and duration; and common intoxication effects, withdrawal symptoms and potential consequences.
Alcohol
Alcohol is fermented from fruits or grains (wine, beer), and fortification (port, sherry), distillation (brandy, whiskey, gin, vodka), vaporization, or condensation can increase its potency. Ethanol content in brewed beverages is measured as “percent” (weight to volume) and in distilled beverages as “proof” units. In the United States, 1 proof means 0.5% alcohol, or twice the percent (eg, 80 proof is 40% alcohol). Ethanol content is highly variable (beer, 3–6%; wine, 12–14%; distilled spirits, 40–60%).
Clinical Pharmacology and Toxicology
Ethanol acts as a central nervous system depressant with local and general anesthetic properties and competes with antidiuretic hormone. During acute intoxication, its actions can result in considerable fluid loss. Ethanol is rapidly absorbed from the stomach (20%) and small intestine (80%). Metabolism occurs almost exclusively in the liver by alcohol dehydrogenase with the remainder excreted in the urine. Blood ethanol level decreases at a fixed rate of about 1 ounce (30 cc) per hour, or 28 mg/dL/hr, or 6 mmol/L/hr.
Consequences of Use
Alcohol use can result in addiction and physical dependence (Table 71-1). Laboratory findings may include elevated osmolar gap, hypokalemia, and metabolic (lactic) acidosis. Hypoglycemia may present as coma or convulsions more than 3 hours postingestion and can occur with blood ethanol levels as low as 50 mg/dL.
Treatment
In the acutely intoxicated patient, management depends on severity. Mild intoxication (< 350 mg/kg of ethanol) can be managed with close observation, hydration, and analgesics. Moderate to severe intoxication (> 350 mg/kg of ethanol, or blood alcohol level [BAL] > 300 mg/dL) requires provision of appropriate airway management and supportive care. Normal doses of activated charcoal do not effectively adsorb ethanol. Hemodialysis should be considered in patients with BAL greater than 500 mg/dL or clinical deterioration despite conservative support.
Treatment for withdrawal depends on the degree of symptoms. In mild withdrawal, rest and hydration are sufficient. For severe symptoms, use of benzodiazepines may be helpful. For seizures, treat with diazepam or phenytoin. For hallucinosis or delirium, treat with haloperidol.
Early intervention in the outpatient setting depends on the degree of the alcohol problem; options range from brief office-based interventions to residential treatment programs. Pharmacologic interventions are limited with regard to adolescent alcohol use disorders.5
Tobacco
Tobacco remains the leading cause of preventable deaths6 in the United States and is one of the most heavily used addictive drugs. Because a majority of chronically addicted adult smokers begin before the age of 18, tobacco dependence should be viewed as a pediatric disease. There is increasing evidence that habituation to tobacco occurs at relatively low levels of use and that the pharmacokinetics of tobacco metabolism may be different in adolescence than in adults.7
Clinical Pharmacology and Toxicology
Derived from the tobacco plant, nicotine is a natural alkaloid and acts as a central nervous system stimulant. Metabolism occurs in the liver and excretion by the kidneys. A single cigarette contains 8 to 9 mg of nicotine, and about 1 mg is delivered to the user while smoking.
Consequences of Use
Nicotine is highly addictive and toxic, and dependence can develop quickly (Table 71-1). In addition to nicotine, tars and other carcinogens in tobacco products are known to be associated with malignancies, and carbon monoxide in smoke is known to increase the risk of cardiovascular disease. Secondhand smoke has also been shown to cause lung cancer in adults and greatly increase the risk of respiratory illnesses in children and of sudden infant death.
Treatment
Withdrawal symptoms are less severe in those who quit gradually. Relapse is frequent, especially in the first few weeks, but diminishes considerably after 3 months. Brief, office-based counseling has been shown to be effective in helping patients consider quitting. Pharmacological combined with psychological treatment results in the highest long-term abstinence rates. Nicotine replacement therapy comes in many forms, such as chewing gum, transdermal patches, nasal sprays, and inhalers. Only nicotine chewing gum and transdermal patches are FDA approved for use in adolescents. Bupropion plus brief counseling has short-term efficacy in helping adolescents quit smoking.8Bupropion helps to control nicotine craving or thoughts about cigarette use.
Cannabis
Cannabis is a collective term for the various preparations of the hemp plant Cannabis sativa. Its potency in street samples has increased over the past 2 decades. It is the most common illicit drug used by children and adolescents in the United States, and its use may precede the use of other more dangerous drugs, is not innocuous, and can have significant social, academic, developmental, and legal ramifications.9
Clinical Pharmacology and Toxicology
The active ingredient in cannabis is Δ-9-tetrahydrocannibol (THC), which is known to bind specific central nervous system receptors. The exact mechanism by which THC produces clinical effects is unknown. The liver metabolizes THC, but 20% is excreted unchanged in the urine and feces. Approximately 20% of an inhaled dose is absorbed, compared to less than 10% after ingestion. THC is highly lipid soluble, and almost 100% is bound to plasma proteins. Regardless of THC content, the amount of tar inhaled and level of carbon monoxide absorbed are 3 to 5 times greater than among tobacco smokers.
Consequences of Use
Animal studies suggest physical dependence can develop, and some people report withdrawal symptoms (Table 71-1). Reproductive effects include gynecomastia (reversible), decreased sperm count and motility (reversible), decreased testosterone levels, and pubertal arrest. Use of cannabis potentiates sedation when used with alcohol and other sedatives.
Treatment
Therapeutic treatment programs may be indicated for chronic users. For acute intoxication, anxiety and panic attacks can be treated with benzodiazepines and a calm environment. Gastric emptying and activated charcoal may be considered for accidental ingestion. No treatment is necessary for withdrawal symptoms.
SCREENING AND COUNSELING
The American Academy of Pediatrics recommends annual screening of adolescents for tobacco, alcohol, and illicit drug use, including other abusable drugs (eg, over-the-counter products, sports supplements, and prescription drugs).10 Beyond the annual visit, it also emphasizes that pediatricians incorporate discussions about substance abuse in all routine health care visit to identify at-risk individuals.11
When obtaining a substance use history, the provider should create an environment of mutual respect and trust and utilize an empathetic approach to engage the adolescent patient. The adolescent patient should be interviewed privately and assessed regarding the types of substances used, route of administration, reason for use, pattern of use (eg, frequency, quantity, binging behaviors), settings in which drug use occurs, and consequences of use including health and legal problems. Also assess for family history of substance abuse and psychiatric illness.
Table 71-1. Common Substances of Abuse by Adolescents*
Optimal prevention counseling on substance use and abuse should be initiated in the preadolescent years, and techniques of using refusal skills should be incorporated as a tool. For alcohol users, counseling should include the consequences of intoxication, particularly drinking and driving. For tobacco and marijuana users, counseling should include advice to quit.
Physician diagnosis and recommendations should be unequivocal and nonjudgmental. Identify the patient’s state of readiness for change using a framework such as Prochaska’s theoretical model for change (or stages of change) to identify whether the patient is in a precontemplative, contemplative, determination, action, or maintenance stage for change.12 Depending on the patient’s stage, the clinician can tailor counseling accordingly. Patient relapse is common, should be anticipated, and should not be considered as failure. It is also common for patients to cycle through stages of change multiple times.
Table 71-2. Substance Use Assessment and Treatment for Adolescents in the Clinical Setting: The 5 A’s Approach
The treatment process must also address the adolescent’s experience, including his or her developmental stage, age, gender, cultural background, disability status, and readiness to change. Coercive pressure to seek treatment is generally not conducive to behavior change. Treatment or placement should depend on where the adolescent falls on the substance use continuum, should involve the family, and, whenever possible, should be adolescent-specific. Programs can include but are not limited to brief office-based interventions, residential treatment programs, cognitive behavioral therapy, motivational interviewing, therapeutic communities, and family therapy (Table 71-2).
SUBSTANCE TESTING
The vast majority of abused substances can be detected in the blood or urine for days to weeks after use (see Table 71-3). Certain drugs, such as γ-hydroxybutyrate, may not be analyzed on standard drug screens. Thus, being familiar with an institution’s drug screens and/or making special requests if testing is indicated may be necessary. In general, testing should be performed on a voluntary basis with the patient’s consent unless the patient lacks decision-making capacity or there are strong medical indications or legal requirements to do so. The American Academy of Pediatrics opposes involuntary testing of adolescents for drugs of abuse and states that laboratory testing for drugs under any circumstances is improper unless the patient and clinician can be assured that the test procedure is valid and reliable and that patient confidentiality is ensured.11 Home and school-based testing is not routinely recommended. Any information obtained from drug screening should be used for therapeutic rather than punitive purposes.
Table 71-3. Urine Drug Testing and Duration of Positivity
COVARIATION OF RISK BEHAVIORS
Risky health behaviors among adolescents covary or cluster in predictable ways.12-15 The onset of one behavior may indicate that another behavior has a greater likelihood of being initiated. A considerable body of research has established links between adolescent substance use and other risky behaviors. The close association of alcohol and unintentional injury is well established.16,17 Alcohol-related motor vehicle injuries are the leading cause of death in late adolescence and early adulthood. Alcohol and illicit drug use are also associated with engaging in fighting at school or at work.18
Substance use is related to early initiation of sexual activity as well as to sexual behaviors that place adolescents at increased risk for unintended pregnancy and sexually transmitted diseases.19 The prevalence of sexual risk behaviors, such as multiple sex partners and not using condoms, is lowest among students who report no substance use, increase among students who use alcohol or cigarettes, and are greatest among those students who use marijuana, cocaine, or other drugs.
Within the area of substance use is a predictable developmental pattern. The use of alcohol and tobacco often occurs before the use of marijuana and is followed by the use of other illicit substances, such as cocaine, psychedelics, heroin, and other nonprescribed stimulants, sedatives, and tranquilizers. The use of a substance farther along the trajectory generally implies ongoing use of the preceding substance, leading to a cumulative effect of all the substances.
Although the passage to adolescence may involve engagement in risky behavior, to focus only on links among risky behaviors fails to explain factors that may reduce the likelihood of negative health and social outcomes.20,21 For example, a sense of parent-family connectedness and school connectedness has been found to protect adolescents against multiple risky behaviors, including use of tobacco, alcohol and marijuana, and initiation of sexual activity. Adolescents with the lowest risk profiles or clusters of risky behavior report high levels of protective factors in the areas of psychosocial adjustment, family, and school. Focusing on decreasing risky behavior and enhancing protective factors is likely to affect both problem and positive behaviors, promoting better outcomes for youth.