Substance Use Disorders - The Dependence of Drugs

The diagnosis of substance use disorders and dependence requires that a person meet three of the following criteria: a preoccupation with the drug, unintentional overdose, tolerance of the drug (they need more to achieve the same high), withdrawal symptoms when the drug is not used, efforts to control use and relapse, abandonment of important social, occupational or recreational activities in order to use the drug more, and continued use despite serious drug-related problems.

a) Alcohol Dependence: Alcohol, a depressant, interferes with higher brain functions, which control behaviour. Long-term overuse of alcohol can cause heart disease, cirrhosis of the liver and brain damage. As well, it may include loss of self-esteem, inability to work, family violence, depression and other psychiatric disorders. People develop their dependency over a long period, over which they generally rely more and more on the mood-altering effects and continually increase their drinking.

b) Nicotine Dependence: Nicotine is even more addictive than alcohol. It is a drug that both stimulates and calms users. Smoking can lead to premature death from heart disease, lung cancer and other respiratory disorders, not only in the smoker but in those around them. The cause is unclear, but many believe that smoking is a learned habit reinforced by pleasurable sensations and associations.

c) Psychoactive Drug Dependence: Psychoactive drugs fall into three main categories – depressants, stimulants and hallucinogens. Depressants cause relaxation, euphoria and addiction. Overuse causes tolerance and extremely uncomfortable and dangerous withdrawal symptoms. Stimulants increase energy, alertness and feelings of confidence. Hallucinogens cause distortion in sensation, however most seem not to be addictive.