POLICE ASSOCIATION OF NOVA SCOTIA 61 drastically reduce their level of use or stop using the drug abruptly, they may experience a variety of signs and symptoms ranging from mild discomfort to seizures. These effects, some of which can be fatal, are collectively referred to as "withdrawal." Withdrawal symptoms are often opposite to the effects produced by taking the drug, e.g. when a person stops using a stimulant drug such as cocaine they may become depressed, need to sleep a lot, and have increased appetite when they awaken. To avoid the discomfort of withdrawal, the person who uses drugs may start to use again or feel unable to stop using the drug. Not all drugs produce physical dependence, but they may still be abused because the person who uses drugs becomes psychologically dependent on the drug's effects. Psychological Dependence Psychological dependence exists when a drug is so central to a person's thoughts, emotions and activities that it is extremely difficult to stop using it, or even stop thinking about it. A strong desire or craving to use a drug may be triggered by internal or external cues such as the end of a meal for smokers or seeing injection equipment for people who inject drugs. Like physical dependence, psychological dependence is a cause of continued drug use. An individual may be both psychologically and physically dependent on a drug. Overdose An overdose of any drug is a dose that can cause serious and sudden physical or mental damage. An overdose may or may not be fatal, depending on the drug and the amount taken. Dangerous overdoses are more likely to occur in people who have developed a tolerance for some effects of a drug more than others, those who return to drug use after a long period of abstinence, or those who use drugs illegally and have no way of knowing the exact potency of what they are buying. Sudden increases in the purity of some illegal drugs (e.g., heroin), have resulted in unintentional fatal overdoses. Hazards of Using Drugs Illegally Using drugs illegally has its own set of risks. People who use drugs that have been obtained illegally can never know exactly what they are taking. Dealers may not know (or reveal) exactly what they are selling. Some drugs are laced with other drugs or chemicals, or contaminated by fungi or moulds, that can be harmful. Often one drug is sold in place of another, e.g., PCP sold as LSD. As a result, many bad drug reactions, including fatal overdoses, have occurred. People who use drugs heavily may use any drug that is available at the right price. As well, people who regularly use drugs illegally, particularly people who inject drugs, are at increased risk for a range of health, legal and social problems. Combining Drugs Many drugs become more dangerous when they are mixed. People may combine drugs intentionally to enhance the effects, or to counteract undesirable side-effects, or they may use a hazardous combination of drugs without intending to do so. For example, they may take sleeping medications after drinking alcohol without being aware that using these drugs together is hazardous. Even if the person is aware that mixing drugs is dangerous, they may do so anyway. Today a mixture of heroin and cocaine is a common example. People who use drugs illegally may mix drugs unknowingly because they do not know what they are taking. Many drugs taken together have the potential to interact with one another to produce greater effects than either drug taken by itself. Or, the combination of drugs may produce a new or unexpected effect. For example, alcohol, opioid analgesics (like codeine), barbiturates (like Seconal®) and benzodiazepines (like Valium®) are all depressant drugs. When taken alone, they can cause relaxation, disinhibition, loss of coordination and sleepiness. If these depressant drugs are taken at the same time, these effects are increased. Such combinations may result in confusion, injuries from falls, depressed breathing, coma and death. Some antidepressants and many drugs taken to treat epilepsy, nausea, allergies and colds also have depressant effects. When taken with other depressants like alcohol, they can dangerously slow or stop breathing. Alcohol can also interact with common medications for heart problems, blood clotting disorders, fungal and bacterial infections, and diabetes, either making them less effective or producing unexpected and undesirable effects. Although classed as a stimulant, cocaine can also cause irregular and shallow breathing. Taking cocaine with heroin, a depressant, increases the risk of death from respiratory depression. Combining drugs may also seriously impair a person's ability to operate a motor vehicle or other machinery. Legal Problems A drug-related conviction can have serious consequences for the individual. The conviction may result in a fine or prison sentence as well as a criminal record. Having a criminal record may restrict employment opportunities and travel outside the country. A subsequent conviction may result in a harsher sentence. Athletes who use a substance that is banned by their local, provincial, national or international sporting organization may be convicted of a doping infraction. This may result in being banned from participating in sports and may also have consequences for their future career opportunities. (...Straight Facts About Drugs and Drug Abuse continued) Health Canada Santé Canada