... 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. ...

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