There are many types of drugs and they all have similar but very different ways of harming you. They also fall into two types of addiction categories, psychological and physical. First of all there are the drugs. These relieve pain by depressing the central nervous system. The main source of these types of drugs is opium. The drug of choice in this category is heroin. Since heroin has high water solubility, preparation for intravenous administration is simple but instant. It produces a sense of inebriation and drowsiness, a deep sense of well-being, but lasts only 3 or 4 hours (Saferstein, 2011 p. 193). Since the effect of this drug lasts only for a certain period, those who use it take it constantly to feel the effect it causes. The more they use this type of drug, the more they will physically crave it. Furthermore, there is a high degree of psychological dependence due to the nature of the drug itself. The sensations it arouses push you to continue using it. Hallucinogens are another type of drug that causes changes in mood, attitudes, processes, and perceptions. Marijuana is the most researched hallucinogen. It is a weed that can grow almost anywhere in any climate. The most potent part of the marijuana plant is its resin. As you move down the power decreases. Most people use one of the lower potency elements such as flowers or leaves. The most potent of all is transformed from resin into liquid hashish. It contains a THC content of between 8 and 20% (Saferstein, 2011 p. 196). Marijuana has no history of physical dependence, although the more you use, the higher your psychological dependence can develop, especially in the more potent uses of marijuana. Intensive use can... half of the paper... d to do this you need to test your hair. The drugs will become permanently trapped in the protein structure of the hair (Saferstein, 2011 p.232). These are the three best ways to test drugs in drug screening. In conclusion, all the drugs mentioned have some type of addiction. It all depends on how you use it, how often and for what purpose. If you only try it once and then never again, you won't get that addiction. However, if you use it and find that you cannot live without the sensations it causes, you will end up with some form of dependence on the drug of your choice. Furthermore, if you think you can fool someone into thinking you haven't taken drugs, you really don't know much about them and their addictions. Works Cited Saferstein, Richard. (2011) Criminalistics: an introduction to forensic science. (10th edition) Upper Saddle River; NJ: Prentice Hall