Stimulant Drugs

Encyclopedia of Childhood and Adolescence, Apr 06, 2001

Stimulants are used for the treatment of certain psychiatric conditions and also used (and abused) for recreational purposes, enhanced levels of energy, and weight loss. They may be prescription or over-the-counter medications, illegal street drugs, or ingredients in commonly ingested substances, such as the caffeine in coffee or the nicotine in cigarettes. Whatever their form, stimulants increase respiration, heart rate, and blood pressure, and their abuse can cause adverse physical effects and endanger a person's health and even his or her life. An overdose of stimulants can result in chest pains, convulsions, paralysis, coma, and death.

The most commonly used stimulant (and the most widely consumed drug) in the United States is caffeine. Found in coffee, tea, soft drinks, chocolate, and drugs, including pain relievers, diet pills, and cold and allergy medications, caffeine belongs to a family of drugs called methylxanthines. It works by disrupting the action of a neurotransmitter called adenosine. Since caffeine is usually consumed in food, it normally enters the body through the gastrointestinal system, passing from the intestines into the blood, which circulates it through the body. It reaches its maximum effect within 30-60 seconds from the time it is consumed, although it remains in the body for several hours. Caffeine is addictive. People who consume it regularly develop a tolerance for it, meaning that they need to ingest progressively greater amounts to continue getting the same effect. (Thus, diet pills containing caffeine lose their effectiveness after a few days, when a tolerance is established.) Caffeine causes physical dependence, producing withdrawal symptoms including anxiety, headaches, and fatigue when its use is discontinued. People who stop using caffeine also experience a craving for it, which is a sign of psychological dependence. In addition to their sugar content, another reason for parents to limit the amount of chocolate and soft drinks their children consume is that excess caffeine can lead to restless, uncontrolled behavior. It is generally agreed that daily caffeine consumption equal to the amount contained in one cup of coffee or soft drink (under 240 milligrams) is probably harmless, but that consumption over 600 milligrams (the amount in four cups of coffee) can cause anxiety, sleep and digestive disorders, a rapid heartbeat, and other health problems. The National College Athletic Association has limited the amount of caffeine that its players can consume.

Besides caffeine, the other stimulant widely ingested is the nicotine consumed in smoking. Both caffeine and nicotine are classified as secondary stimulants because, unlike drugs such as amphetamines and cocaine, they affect the sympathetic nervous system more than the central nervous system. Also unlike stimulants that are abused for recreational purposes, caffeine and nicotine produce only an increased energy level but not a feeling of intoxication. Nicotine acts mostly as a stimulant in new users, but long-term users claim that it relaxes them. Teenage smoking has been rising steadily throughout the 1990s. A 1995 survey of high school students by the Centers for Disease Control and Prevention found that on average 34.8% of teenagers smoke. Like users of other addictive substances, teen smokers start out thinking they will be able to control their use of cigarettes, but two-thirds of young people who smoke have tried to quit and failed. Nicotine withdrawal symptoms include anxiety, irritability, insomnia, depression, headaches, mood swings, difficulty concentrating, and changes in appetite. Teen smokers who want to quit can obtain help from support groups such as Nicotine Anonymous and call-in hotlines and from their family physicians, who may prescribe medications to reduce withdrawal symptoms.

Stimulant drugs have long been used to treat psychological disorders. In the past psychiatrists used certain stimulants as antidepressants , but today this practice is confined primarily to seriously depressed patients who have failed to respond to either psychotherapy or to the wide range of other antidepressants that are currently available (and that, unlike stimulants, are not addictive). Today the primary therapeutic use of stimulants is the treatment of attention deficit/hyperactivity disorder (ADHD) in children, and the most widely used drug is Ritalin (methylphenidate) . Ritalin works by facilitating the release of the neurotransmitter norepinephrine, which improves alertness, attention span, and the ability to focus. Hyperactive children taking Ritalin are less impulsive, have better self-control, and make fewer errors in their schoolwork. They also get along better with their peers. Developed in 1956, Ritalin has been tested in over 200 studies--more than any other drug used for children. It is officially approved by the FDA for use in treating ADHD. Daily dosage of the medication (usually administered two or three times a day) ranges from 10 milligrams to as high as 80, with most children taking between 30 and 70 milligrams a day. Although it is generally considered safe and effective for the treatment of ADHD, there is still controversy surrounding the frequency with which this medication--whose use by children doubled between 1988 and 1994--is prescribed. Side effects include insomnia, appetite loss, and stomach pains. Ritalin may also produce withdrawal symptoms, including headache, irritability, nausea, and abnormal chewing movements and movements of the tongue. Ritalin can also interfere with a child's rate of growth, and some physicians recommend a "drug holiday" of several weeks a year for children taking the medication to help them catch up on growth that may have been delayed by the drug (and also to assess their condition). Other stimulants used for ADHD (usually when Ritalin doesn't work or produces too many negative side effects) are Dexedrine and Cyclert (pemoline), a stimulant similar to Ritalin. Psychiatrists also prescribe Ritalin, Cyclert, and Dexedrine to improve attention span and reduce hyperactivity in children with pervasive developmental disorder (PDD) and autism. An important effect of this treatment is that it makes these children more receptive to psychotherapy. Ritalin and other stimulants have also been prescribed to prevent daytime sleep episodes in persons suffering from severe narcolepsy.