Amphetamines and related disorders Health Article

Definition

Amphetamines are a group of powerful and highly addictive substances that dramatically affect the central nervous system. They induce a feeling of well-being and improve alertness, attention, and performance on various cognitive and motor tasks. Closely related are the socalled "designer amphetamines," the most well known of which is the "club drug" MDMA, best known as "ecstasy." Finally, some over-the-counter drugs used as appetite suppressants also have amphetamine-like action. Amphetamine-related disorders refer to the effects of abuse, dependence, and acute intoxication stemming from inappropriate amphetamine and amphetamine-related drug usage.

Description

Several amphetamines are currently available in the United States. These include dextroamphetamine (Dexedrine), methamphetamine (Desoxyn), and methylphenidate (Ritalin). These Schedule II stimulants, known to be highly addictive, require a triplicate prescription that cannot be refilled. Amphetamines are also known as sympathomimetics, stimulants, and psychostimulants. Methamphetamine, the most common illegally produced amphetamine, goes by the street name of "speed," "meth," and "chalk." When it is smoked, it is called "ice," "crystal," "crank," and "glass." Methamphetamine is a white, odorless, bitter-tasting crystalline powder that dissolves in water or alcohol.

The leaves of the East African bush Catha edulis can be chewed for their stimulant effects. This drug, cathinone or Khat, has an effect on most of the central nervous system, in addition providing the other properties of amphetamines. Illegal laboratories have begun making methcathinone, which has effects similar to cathinone. Methcathinone, also known as "crank," is easily synthesized from ephedrine or pseudoephedrine.

Amphetamines were initially produced for medical use, and were first used in nasal decongestants and bronchial inhalers. Early in the 1900s, they were also used to treat several medical and psychiatric conditions, including narcolepsy (a rare condition in which an individuals falls asleep at dangerous and inappropriate moments and cannot maintain normal alertness), attention-deficit disorders, obesity, and depression. They are still used to treat these disorders today.

Amphetamine-like substances called ephedrine and propranolamine are available over the counter in the United States and are used as nasal decongestants. Phenylpropanolamine is also used as an appetite suppressant, and is available over the counter as well. These are less potent than the classic amphetamines, but are still subject to abuse, partly because of their ready availability and low price.

In the 1970s, governmental agencies initiated restrictions increasing the difficulty of obtaining amphetamines legally through prescription. During this same time period, a drug chemically related to the amphetamines began to be produced. This so-called designer drug, best known as "ecstasy," but also as MDMA, XTC, and Adam, has behavioral effects that combine amphetamine-like and hallucinogen-like properties.

The structure of amphetamines differs significantly from that of cocaine, even though both are stimulants with similar behavioral and physiological effects. Like cocaine, amphetamine results in an accumulation of the neurotransmitter dopamine. It is this excessive dopamine concentration that appears to produce the stimulation and feelings of euphoria experienced by the user. Cocaine is much more quickly metabolized and removed from the body, whereas amphetamines have a much longer duration of action. A large percentage of the drug remains unchanged in the body, leading to prolonged stimulant effects.

The handbook that mental health professionals use to diagnose mental disorders is the Diagnostic and Statistical Manual of Mental Disorders, also known as the DSM. The 2000 edition of this manual (the Fourth Edition Text Revision, also known as DSM-IV-TR) describes four separate amphetamine-related disorders. These are:

• Amphetamine dependence, which refers to chronic or episodic binges (known as "speed runs"), with brief drug-free periods of time in between use.
• Amphetamine abuse, which is less severe than dependence. Individuals diagnosed with amphetamine abuse have milder but nevertheless still substantial problems due to their drug usage.
• Amphetamine intoxication, which refers to serious maladaptive behavioral or psychological changes that develop during, or shortly after, use of an amphetamine or related substance.
• Amphetamine withdrawal, which refers to symptoms that develop within a few hours to several days after reducing or stopping heavy and prolonged amphetamine use. Withdrawal symptoms are, in general, opposite to those seen during intoxication and include fatigue, vivid and unpleasant dreams, insomnia or hypersomnia (too much sleep), increased appetite and agitation or slowing down.