Drugs and their effect on the limbic system of the brain.

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Drugs

Most of the drugs that people abuse have their effect on the limbic system of the brain. The limbic system is located deep within the brain near the top of the brain stem. The limbic system produces the feelings of pleasure, pain, anger, and fear which characterize our emotions. All drugs of addiction work on our emotions. If a certain drug makes us feel very good, we tend to want to take that drug again and again. It is because of this temporary good feeling that we become psychologically addicted to a drug.

Within the limbic system, drugs work on the brain by way of neurotransmitters. Neurotransmitters are the chemicals which allow our nerve cells to communicate with each other. Some of the neurotransmitters affected by drugs are serotonin, norepinephrine and dopamine. The class of drugs called stimulant drugs will usually make more a neurotransmitter(s) available to the brain. The class known as depressant drugs will usually make less of a neurotransmitter(s) available to the brain. Because our brain adjusts to this alteration in neurotransmitters, our brain may become physiologically (physically) dependent on some drugs. Although our brain can become physiologically dependent on a wide variety of drugs, the brain is more likely to become dependent on depressant drugs than on stimulant drugs.

As drugs appear in nature they can be addictive. However, it is technology which makes them very addictive. Opium, a drug which occurs naturally in the white poppy plant, is classed as a narcotic. A narcotic drug relieves pain and induces sleep. The brain has neurotransmitters which controls our perception of pain. These neurotransmitters are called endorphins. Within the brain, endorphins mask pain and make us feel good. All opium products are chemically similar to endorphins and have their pleasurable effects by substituting for endorphins in our brain.

Opium has been used and abused since the beginning of recorded history. There is a reference to opium in Homer's Odyssey written in the sixth century BCE. People have for centuries eaten and smoked opium. Some of these people became addicted to it, others did not. However, in the mid 1800's, opium was refined into morphine and codeine. Morphine and codeine magnified the power of opium ten times. Also in the mid 1800's, the hypodermic needle was invented. If the hypodermic needle is used to intravenously inject morphine, it magnifies the power of the drug 10-15 times.

In 1896 opium was further refined into diacetylmorphine, which became known as heroin. It was named heroin because they thought it was a "hero" drug. It was believed to be nonaddictive, and for years was a treatment for alcoholism. Alcoholics were advised to stop drinking and substitute heroin use instead. This was reasonably good therapy because heroin is not as damaging to the physical body as is alcohol. However, it is far more addictive and damaging to the mind. When the hypodermic needle is used to intravenously inject heroin, addiction develops quickly.

Heroin is a drug to which people become both psychologically and physiologically (physically) dependent. It is a drug of escape. When heroin is intravenously injected, called mainlining, it creates a rush of excitement followed by a peaceful, calm euphoria. Heroin becomes the only thing of importance to the addict. Family, friends and work all become secondary to heroin. Since addiction to heroin makes it difficult to hold a job, crime becomes the primary way to buy heroin. Heroin addicts often become shoplifters, prostitutes and drug dealers. Heroin produces good feelings which normal living cannot match. Once the drug user experiences these great feelings of euphoria, normal feelings lose their value.

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If a person must withdraw from heroin, physical dependence causes severe withdrawal symptoms. Withdrawal begins 6-12 hours following their last injection, and withdrawal symptoms include: weakness, nervousness, sweating, insomnia, shaking, convulsions, hallucinations, vomiting, diarrhea, and an involuntary movement of the arms and legs. It is from this involuntary movement of the legs that came the expression "kicking the habit." Since withdrawal from heroin can result in death, it is best to withdraw with medical help. Physicians can administer an anti-seizure medication called Dilantin to reduce seizures, and an anti-anxiety agent (tranquilizer) such as Librium to calm the nervousness and shakes.

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