A bit of history To understand heroin and its effects, you have to know something about opiates - a group of drugs found in the juice extracted from the seed pod of the Asian poppy. These drugs include opium and its constituents, codeine and morphine, and their derivatives - one of which is heroin. Opiates have been around quite literally for centuries, and used for both medical and non-medical purposes. Most street preparations of heroin contain only a small percentage of the drug and are diluted with sugar or other substances. The trouble with heroin is that you can never be sure how long it will take before you become dependent on it.
Some people can use it once in a while over a long period of time before becoming addicted.
Others get addicted right away. And that's how people get addicted. It feels good enough to try again. No wonder so much crime is heroin-related. Such single-mindedness is the most obvious characteristic of the heroin addict.