PATHOPHYSIOLOGY

Substance-related disorders are a major public health problem affecting young people in the United States. They are the leading cause of preventable death in 15- to 24-year-olds. Substances used can be any of a number of drugs taken for toxic or side effects. Such substances include alcohol, amphetamines, cannabis, cocaine, hallucinogens, inhalants, nicotine, opioids, anxiolytics, and phencyclidine (PCP). The effects of substance intoxication vary widely depending on the individual and the substance used. Generally, intoxication causes physiologic, cognitive, and psychosocial effects. A diagnosis of substance abuse is made when drug use causes adverse consequences such as physically hazardous behaviors, legal problems, and interference with school functioning.

A more serious problem is substance dependence. Prolonged, heavy use of a substance results in dependence. Over time, increasing amounts of the substance are needed to achieve intoxication; this is referred to as tolerance. When blood concentrations of the substance diminish, unpleasant withdrawal symptoms are experienced. Once dependence develops, the individual uses the substance primarily to relieve withdrawal symptoms. Withdrawal from certain drugs such as alcohol and benzodiazepines (e.g., Valium) is potentially life threatening. Hospitalization to manage detoxification may be indicated.

Alcohol, tobacco, and marijuana are the substances most frequently abused by children and adults. Inhalant use, which is often perceived as harmless by adolescents, accounts for a large number of deaths of teenagers. Both inhalant and heroin use are on the rise in the United States. Steroids are also one of the drugs being used with increased frequency by adolescents. Steroids became popular in athletics to improve performance by increasing muscularity. Because steroids do not increase endurance, they are mostly used by athletes who participate in football, wrestling, weight lifting, powerlifting, and bodybuilding.

The use of steroids by adolescents may or may not be for sports performance. Some abusers of steroids have muscle dysmorphia or “bigorexia,” which is when an individual is obsessed with being unreasonably muscular and with low body fat. Some see muscle dysmorphia as an antithesis to anorexia nervosa. The connection is strengthened by the fact that many male and female steroid abusers have been victims of sexual and physical abuse.

Most steroid abusers are considered to be psychologically normal when they start using steroids. Gym dosing is typically 10 to 100 times the dosage for medical use. As with other illicit drugs, the problem with steroids is cessation. One of the major consequences of cessation of administration is depression. Use has decreased, possibly because of the press given to negative consequences suffered by professional athletes. Programs that have failed to reduce steroid use are drug testing–only programs, physical training or nutrition education, and education-only programs that do not focus on changing the perception of risk.

A number of psychosocial, developmental, cultural, attitudinal, and personality factors put a youth at risk for drug experimentation. The most significant predictor for substance use is drug use by peers. Other risk factors include poor self-image, problems with school performance, difficult temperament, hyperactivity, and genetic predisposition. Risk factors include problems associated with family dysfunction, including abuse and neglect, overly rigid or permissive parents, parental rejection, and divorce. The following are factors associated with resistance to illicit substance use: nurturing parents, positive school experience, negative attitudes toward drugs, committed religious attitudes, positive self-esteem, and social competence.

Generally, the younger the age of initial drug use, the higher the risk for serious long-term health consequences and adult abuse. Cigarette, alcohol, and marijuana use has been associated with ready access to these substances in the child’s home.

Gateway phenomenon is a term denoting the pattern of using an increasing variety of substances, ultimately leading to polysubstance abuse. Evidence for this phenomenon is that youth who smoke tobacco and drink alcohol are more likely to use marijuana, and those who use marijuana are more likely to use cocaine. An adolescent may initially begin using to achieve a false sense of maturity, but eventually he or she is likely to develop drug dependence. Substance abuse is associated with depression, low self-esteem, risk for school underachievement, teenage pregnancy, and delinquency. Illicit drug use creates a greater risk of contracting human immunodeficiency virus (HIV) infection and hepatitis C.

Box 73-1 presents the criteria from the American Psychiatric Association’s Diagnostic and statistical manual of mental disorders (DSM IV-TR) for substance abuse, substance dependence, substance intoxication, and substance withdrawal.

INCIDENCE