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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.

Symptoms

CLASSIC AMPHETAMINES.According to the DSM-IVTR, symptoms of heavy, chronic, or episodic use of amphetamine, known as amphetamine dependence, can be very serious. Amphetamine dependence is characterized by compulsive drug-seeking and drug use leading to functional and molecular changes in the brain. Aggressive or violent behavior may occur, especially when high doses are ingested. The individual may develop anxiety or paranoid ideas, also with the possibility of experiencing terrifying psychotic episodes that resemble schizophrenia, with visual or auditory hallucinations, delusions such as the sensation of insects creeping on the skin, known as "formication." hyperactivity, hypersexuality, confusion, and incoherence. Amphetamine-induced psychosis differs from true psychosis in that despite other symptoms, the disorganized thinking that is a hallmark of schizophrenia tends to be absent. Amphetamine dependence consistently affects relationships at home, school and/or work.

Amphetamine abuse is less serious than dependence, but can cause milder versions of the symptoms described above, as well as problems with family, school, and work. Legal problems may stem from aggressive behavior while using, or from obtaining drugs illegally. Individuals may continue to use despite the awareness that usage negatively impacts all areas of their lives.

Acute amphetamine intoxication begins with a "high" feeling which may be followed by feelings of euphoria. The user experiences enhanced energy, becoming more outgoing and talkative, and more alert. Other symptoms include anxiety, tension, grandiosity, repetitive behavior, anger, fighting, and impaired judgment.

In both acute and chronic intoxication, the individual may experience dulled feelings, along with fatigue or sadness, and social withdrawal. These behavioral and psychological changes are accompanied by other signs and symptoms including increased or irregular heartbeat, dilation of the pupils, elevated or lowered blood pressure, heavy perspiring or chills, nausea and/or vomiting, motor agitation or retardation, muscle weakness, respiratory depression, chest pain, and eventually confusion, seizures, coma, or a variety of cardiovascular problems, including stroke. With amphetamine overdoses, death can result if treatment is not received immediately. Long-term abuse can lead to memory loss as well, and contributes to increased transmission of hepatitis and HIV/AIDs. Impaired social and work functioning is another hallmark of both acute and chronic intoxication.

Following amphetamine intoxication, a "crash" occurs with symptoms of anxiety, shakiness, depressed mood, lethargy, fatigue, nightmares, headache, perspiring, muscle cramps, stomach cramps, and increased appetite. Withdrawal symptoms usually peak in two to four days and are gone within one week. The most serious withdrawal symptom is depression, possibly very severe and leading to suicidal thoughts.

DESIGNER AMPHETAMINES.Use of so-called designer amphetamines, the best-known of which is MDMA, leads to symptoms of classic amphetamine use. Users report a sense of feeling unusual closeness with other people and enhanced personal comfort. They describe seeing an increased luminescence of objects in the environment, although these hallucinogenic effects are less than those caused by other hallucinogens, such as LSD. Some psychotherapists have suggested further research into the possible use of designer amphetamines in conjunction with psychotherapy. This idea is highly controversial, however.

Like classic amphetamines, use of MDMA produces cardiovascular effects of increased blood pressure, heart rate, and heart oxygen consumption. People with preexisting heart disease are at increased risk of cardiovascular catastrophe resulting from MDMA use. MDMA is not processed and removed from the body quickly, and remains active for a long period of time. As a result, toxicity may rise dramatically when users take multiple doses over brief time periods, leading to harmful reactions such as dehydration, hyperthermia, and seizures.

MDMA tablets often contain other drugs, such as ephedrine, a stimulant, and dextromethorphan, a cough suppressant with PCP-like effects at high doses. These additives increase the harmful effects of MDMA. It appears also to have toxic effects on the brain's serotonin system. In tests of learning and memory, MDMA users perform more poorly than nonusers. Research with primates show that MDMA can cause long-lasting brain damage. Exposure to MDMA during the period of pregnancy in which the fetal brain is developing is associated with learning deficits that last into adulthood.