Also called psychostimulants, stimulants are drugs that produce increased levels of mental and physical energy and alertness and an elevated mood by stimulating the central nervous system.
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).
The primary modern therapeutic use of stimulants is the treatment of narcolepsy and attention deficit hyperactivity disorder (ADHD) in children. The most widely used drug for these purposes is Ritalin (methylphenidate). Developed in 1956, methylphenidate has been tested more than any other drug used in treating children. The way in which Ritalin acts is not completely clear, but a study that used positron emission tomography (PET scans) to look at activity in the brain seemed to indicate that methylphenidate increases the release of the neurotransmitter dopamine. In normal individuals, methylphenidate causes restlessness and wakefulness, but it appears to help individuals with ADHD calm down, improve their ability to focus, and help them control symptoms of the disorder such as restlessness, inattention, and impulsivity. Hyperactive children taking Ritalin have better self-control and make fewer errors in their schoolwork. They also get along better with their peers.
Other stimulants used therapeutically, such as Dexedrine, Adderall, and Concerta, may be prescribed when Ritalin does not work or produces too many negative side effects. Psychiatrists also sometimes prescribe these stimulants to improve attention span and reduce hyperactivity in children with pervasive developmental disorders (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.
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. Stimulants may be prescription or over-thecounter medications, illegal street drugs, or ingredients in commonly ingested substances, such as the caffeine in coffee and 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, energy drinks, chocolate, and drugs, including pain relievers, diet pills, and cold and allergy medications, caffeine belongs to a family of drugs called methylxanthines. Caffeine works by binding with adenosine receptors in the brain and increasing the amount of the neurotransmitter dopamine. 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 is absorbed almost immediately, reaches its maximum effect within 30–60 minutes from the time it is consumed, and remains in the body for several hours.
Besides caffeine, the other stimulant widely ingested is the nicotine taken in while 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 do not produce a feeling of intoxication. Nicotine acts paradoxically mostly as a stimulant in new users, but as a relaxant in long-term users. Nicotine withdrawal symptoms include anxiety, irritability, insomnia, depression, headaches, mood swings, difficulty concentrating, and changes in appetite.
The primary illegal stimulants used for recreational purposes are amphetamines and cocaine. Amphetamines produce an effect similar to that of the hormone adrenaline, making users feel awake, alert, and energetic. Drugs of this type were abused by young people as early as the 1930s, when it was popular to tear the medicated strips out of Benzedrine nasal inhalers and ingest them directly or in coffee. By the 1950s and 1960s amphetamines were widely used by people who needed to keep themselves awake through the night, such as truck drivers and jazz musicians, or by athletes for extra energy. Many young people used them to stay awake when they needed to study for tests or complete school assignments. It is Page 2541 | Top of Articleestimated that up to half the amphetamines sold by drug companies in the 1960s were sold illegally. After the government imposed controls on the manufacture of these drugs, they began to be produced illegally in home laboratories. Not only are these preparations vulnerable to contamination, they are often diluted by manufacturers and dealers. Many supposed amphetamines sold on the street contain mostly caffeine and other drugs, with a very small percentage of amphetamine or even none at all.
The use of amphetamines declined in the 1980s as cocaine became the drug of choice. However, since the 1990s, methamphetamine has become increasingly popular, especially among middle-class suburban teenagers, in a crystalline form—known as ice, L.A. ice, or crank—that can be smoked, snorted, injected, or ingested. Smoking methamphetamine first became fashionable in Hawaii. In 2003, more than 40% of men arrested in Honolulu tested positive for methamphetamine. Use of the drug then became widespread in California and the Pacific Northwest, and eventually spread eastward to other parts of the country. In 2013, 3.3% of high school seniors in the United States reported having used methamphetamine at least once. Users like it because it reaches the brain almost immediately, and its effects last longer than those of cocaine. It produces feelings of alertness, euphoria, and increased energy. Like other amphetamines, crank also decreases appetite and promotes weight loss, making it attractive to young women.
A related stimulant, which is derived from methamphetamine, is MDMA, also known as ecstasy. MDMA combines the characteristics of a stimulant and a psychedelic drug, producing hallucinations and enhanced feelings of sociability and closeness to others. It is less addictive than amphetamines but more dangerous. People have died from taking this drug; some had preexisting heart conditions, but others had no known medical problems. MDMA causes brain damage, and its use can lead to the development of panic disorder.
Cocaine is a stimulant made from the leaves of the coca plant. Its street names include coke, snow, toot, blow, stardust, nose candy, and flake. When the pure drug was first extracted from the leaves in the nineteenth century, its harmful effects—including addiction—were not known, and early in the twentieth century it was legally sold in medicines and soft drinks, including Coca-Cola, which originally contained small amounts of the substance (from which its name is derived). Cocaine use has been illegal since 1914. Until the 1970s it was not widely used except among some members of the arts and entertainment community. At first cocaine was largely used in a diluted powder form that was inhaled. Eventually, more potent smokable forms were developed. Cocaine became visible as a substance abused by celebrities, including the actor John Belushi (who died of a cocaine-heroin overdose); the comedian Richard Pryor (who was badly burned freebasing cocaine); and the former District of Columbia mayor Marion Barry, who was forced to resign from office but later reelected. Cocaine use tends to be highest in urban areas.
Methylphenidate comes in a variety of strengths and forms—tablets (both short acting and slow release), chewable tablets, and liquid. In 2006, a skin patch (Daytrana) was approved for use in children ages 6–12. Treatment with drugs such as Ritalin usually begins with two low doses taken at breakfast and lunch, or one slowrelease dose taken in the morning that lasts all day. The dosage is gradually increased under a physician's supervision until a therapeutic level is reached.
Stimulant drugs are subject to abuse and development of tolerance except when the drugs are appropriately used for a proper diagnosis of ADHD.
When used to treat young children, there is some evidence that stimulant drugs reduce the rate of growth. This lower growth rate may be made up for by a growth spurt when the drugs are discontinued.
Stimulant drugs also increase blood pressure.
Although stimulants are generally considered safe and effective for the treatment of ADHD, there is still Page 2542 | Top of Articlecontroversy surrounding the skyrocketing frequency with which stimulants are prescribed for young children. 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. Some physicians recommend a drug-free period of several weeks each year to help alleviate side effects and assess the condition of children taking the drug.
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 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 mg) is probably harmless, but that consumption over 600 mg (the amount in four cups of brewed 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 acceptable in urine tests of student athletes to 15 micrograms per mL. (For reference, two cups of black coffee will result in urine levels of about 3–6 micrograms per mL.)
Cocaine produces a physical addiction by affecting the brain's chemistry and a psychological addiction because users become dependent on the confident, euphoric feeling it creates to help them cope with the stresses of daily life. Possible negative reactions to large doses of cocaine use include hallucinations, paranoia, aggressive behavior, and even psychotic breaks with reality. Cocaine can cause heart problems, seizures, strokes, and coma. Reactions to withdrawal from the drug are so severe that most users are unable to quit without professional help. Withdrawal symptoms, which may last for weeks, include muscle pains and spasms, shaking, fatigue, and reduced mental function. Both inpatient and outpatient programs are available to treat persons for cocaine addiction. Although such programs are costly, treatment expenses for teenagers are often covered by their parents' health insurance plans or HMOs. Some treatment facilities also have provisions to waive fees for a certain number of low-income patients.
People who abuse methamphetamine, which remains in the body for as long as four days, quickly establish a tolerance for the drug and require ever greater amounts to experience the same effect. Users can become addicted rapidly, especially when the drug is injected. Side effects of the drug include jitteriness, dry mouth, sweating, diarrhea, insomnia, anxiety, and blurred vision. Severe reactions can include hallucinations (called “tweaking”), paranoia, and speech disorders, all of which may persist for up to two days after use of the drug. In addition to physical addiction, amphetamines produce a psychological dependency on the euphoric effects produced by these drugs, especially because when they wear off they are followed by a “crash” that produces a depression so severe it can lead to suicide.
If taken correctly and under the direct supervision of a physician, stimulant drugs such as Ritalin have no interactions with drugs that are normally prescribed for children.
ADHD is a difficult diagnosis and may be confused with normal childhood energy. Stimulants should not be used to calm an active child for the convenience of parents or babysitters. A diagnosis should be made and drug therapy initiated only by a qualified professional experienced in this condition.
Children who fail a trial of one stimulant may respond to another drug in the same class. A child who does poorly on methylphenidate may respond to amphetamines and vice versa. There is some dispute over the lowest age at which stimulant therapy may be appropriately started, but it seems agreed that these drugs should not be used to treat children under the age of three years.
Methylphenidate and amphetamines must be kept out of reach of children, particularly visitors and older siblings of a child being treated for ADHD due to their highly addictive nature. Because of the risk of growth suppression, stimulant drugs should be administered only during school periods.
Sometimes, drugs that are properly prescribed for ADHD are diverted and used by other children as recreational drugs. If a child who has been well stabilized on stimulants for ADHD begins to get worse, parents may need to consider the possibility that the drugs are being sold or given to others, rather than being used therapeutically. Stimulant drugs should be administered by a parent, guardian, school nurse, or other responsible adult. This precaution will both guard against diversion and ensure that children are not forgetting to take their medication.
Signs of possible stimulant abuse include dilated pupils, frequent lip licking and dry mouth, excessive activity, and lack of sleep. The drug abuser becomes talkative, but the discussion lacks continuity or coherence, and the subject of conversation changes frequently.
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