The Effects of Substance Abuse on Adolescent Development

Substance abuse carries many risks to adolescents and society. Substance abuse includes alcohol and drug use and addiction. The effects and risks of substance abuse include traffic accidents, risky sexual behavior, juvenile delinquency, sub-par academic performance, and developmental problems in the adolescent brain. Some of these effects can lead to death or permanent injury or disability. Other effects, including developmental effects that hinder the proper development of the brain, can have a lifelong impact on a person's ability to reason and/or use sound judgment.

Instances of Alcohol and Drug Abuse In Adolescents

• Approximately 1.1 million adolescents in the United States are dependent on illegal drugs. Adolescents are defined as children between the ages of 12 and 17. A further 915,000 adolescents are addicted to alcohol.
  55% of high school seniors have tried illegal drugs. 29% of high school seniors have tried a "harder" drug than marijuana. Hard drugs are defined as cocaine, inhalants, heroin, and other miscellaneous drugs including prescription medicine, acid, and various other tranquilizers and mind-altering drugs. Children between the ages of 18 and 20 have the highest rate of illicit drug use, at 19.9% of the population, while children ages 16 to 17 have the second highest rate at 16.4%.
  Approximately 10.4 million children between the ages of 12 and 20 drink. Of these adolescent drinkers, 5.1 million engage in binge drinking, which is defined as drinking 4 or more alcoholic beverages in one sitting.
  Approximately 25% of children between the ages of 10 and 17 report on surveys that their friends inhale fumes from household products including glue and paint.

Development of the Adolescent Brain

• Many important brain structures achieve much of their growth during adolescence. The prefrontal cortex, which controls planning, impulse control, risk assessment, consequence prediction, and organization, develops in adolescence. The limbic system controls emotions, dreams and goals. The cerebellum controls coordination, movement, emotional maturity, and cognition or understanding. The corpus callosum controls the neurotransmitters and receptors in the brain and dictates how quickly we can access information. The hippocampus controls memory functions. Each of these essential parts of the brain primarily develops during adolescence. Interrupting the development of these bran functions can have lifelong effects.

Effects of Alcohol on Adolescent Brain Development

• The adolescent brain is not fully developed, which creates a number of problems for teenagers and young adults who imbibe alcoholic beverages. Animal tests done on adolescent rates suggest that permanent damage can occur to the neurochemical, cellular, synaptic and structural organization of the brain if adolescents binge drink.
  Those adolescents affected by Alcohol Use Disorder (AUD) can experience brain changes that result in decreased problem solving ability, difficulty with verbal and non-verbal retrieval, hindered visuospatial skills, and a slower or less effective working memory. AUD is defined as both alcohol use and alcohol dependence.
  Drinking alcohol can also cause or worsen abnormalities in the frontal limbic system. The frontal limbic system deals with emotional reactivity, and a damaged limbic system may be partially responsible for the association between adolescent drinking and antisocial behavior. This antisocial behavior can include conduct disorders, including persistent aggressive behavior and/or a lack of respect for social standards of conduct. Antisocial behavior also includes poor self control, poor decision making, and poor behavior regulation. The cause and effect relationship between problems with the limbic system and alcohol is unclear; it is possible the alcohol causes the problems, but it is also possible that kids with conduct problems already have weakened limbic systems, and thus it is these conduct problems that cause them to be substance abusers.
  Blackouts, or alcohol induced amnesia in which a person does not remember events or behavior, are also common among adolescent drinkers. This is due in part to the effect of alcohol on neural plasticity in the hippocampus. The hippocampus is involved in the formation of new memories, and it can be disrupted by excessive drinking.
  As heavy drinking continues, the brain becomes less able to compensate for the disruptions caused by the effects of alcohol. Thus, the more a teen drinks, the higher the chances for developing permanent neuronal damage.

Marijuana Use and The Adolescent Brain

• Chronic, heavy use of marijuana by adolescents can also cause developmental issues. Adolescents who are defined as heavy marijuana smokers tend to perform worse on thinking tasks than their non-drug using peers. Marijuana users also have slower psychomotor speeds, poorer complex attention, weaker verbal memory, and impaired planning abilities. Although studies suggest that verbal memory function can be partially recovered within three weeks of discontinuing marijuana use, complex attention skills do not recover.
  Studies have shown that neurological consequences of marijuana use are especially pronounced for females. Girls who used marijuana in their teens were found to have significantly larger prefrontal cortex (PFC) volumes when compared with non-smoking teen girls. Larger PFC volumes are associated with impaired planning ability, poor decision making, and a reduced attention span when focusing on a task.
  Additional studies have suggested that both young men and women suffer consequences from adolescent marijuana use. Marijuana, especially excessive smoking, can arrest development of the myelin sheath which surrounds brain cells. Myelin provides an insulation around cells that is similar to that covering electrical wires. Without proper myelin coting, signaling within the brain may be slower or impaired.

Other Drugs and the Adolescent Brain

• Studies performed on monkeys suggests that the drug ecstasy can permanently damage neurons. Monkeys who received ecstasy had far less serotonin than monkeys in the control group. This suggests that the serotonin neuron terminals were destroyed by ecstasy. The study also demonstrated that the damage was long term, because 7 years after ecstasy use, monkeys still had reduced levels of serotonin although there was a partial recovery.
  Studies have also demonstrated that adolescents may be more sensitive to addictive drugs including cocaine and amphetamines. These adolescents were more sensitive even than newborns to the effects of these highly addictive drugs. On a study performed adolescent mice, those given cocaine were found to have a greater increase in protein in the striatum. This protein, called Delta FosB, regulates the use of genes. An increase on Delta FosB could affect other areas of the brain, leading to long-lasting changes.