xamples include some of the major abused drugs รป opium, alcohol, cocaine, and barbiturates. Other drugs, such as marijuana and the hallucinogens appear to produce habituation in humans even though they are not powerful reinforcers for laboratory animals (Wright, 1999, p. 47)
Substances that are abused must also be distinguished by the fact that while almost all of those noted above are illegal to possess (or in many cases illegal to possess without a prescription), tobacco and alcohol are legal for adults to possess and consume. It is no doubt partly the legal status of these drugs that leads to their being so commonly abused, but one can assume that these drugs would also be likely to be abused even if they were not legal because they are physically and psychologically so habituating.
Nor, of course, can it be assumed that simply because alcohol and tobacco are legal that they are safe, or even relatively safe. Tobacco use can lead to a variety of potentially fatal illnesses, including lung and throat cancer and emphysema and can increase the chance of contracting other potentially fatal diseases such as breast cancer and heart disease. Alcoholism can lead to liver disease, brain disease and also contributes to other potentially lethal conditions. The effect of alcohol on major organ systems is cumulative and includes a wide range of digestive-system disorders such as ulcers, inflammation of the pancreas, and cirrhosis of the liver. The central and peripheral nervous systems can be permanently damaged. Blackouts, hallucinations, and extreme tremors may occur.
In general, treatment of substance abuse in the United States increasingly recognizes the abuse itself as the primary problem needing attention, rather than regarding it as always secondary to another, underlying problem. Specialized residential treatment facilities and separate units within general or psychiatric hospitals are rapidly increasing in number. As the publi...