Long-term substance abuse of legal and illegal substances causes millions of deaths and costs billions for medical care and substance abuse rehabilitation. The effects of drug abuse extend beyond users, spilling over into the larger society, imposing social and economic costs.
The U.N. International Drug Control Program (UNDCP) estimates drug abuse in the United States costs the nation more than £48 billion a year, which translates to about 1.3 per cent of the nation's gross domestic product. In addition, incarceration of drug offenders has helped jam the nation's prisons. For other nations, drug abuse also imposes large costs, as shown in reports by UNDCP.
Physiological effects of drug abuse vary by the type of drug. Stimulants, such as amphetamines, can delay sleep and elevate a person's mood, but high amounts can cause nervousness and anxiety in the user. Depressants, by contrast, impair mental and physical functions, and slow neural activity in the brain. With some drugs, especially narcotics such as opium or heroin, the body can build a tolerance in which it adjusts to the drug's presence. Over time, the body requires higher doses to maintain the same effect. When an abuser stops taking the drug, the body experiences withdrawal symptoms, such as feeling weak or sick. Withdrawal symptoms are the body's reaction to the absence of the drug to which it had become adjusted.
The social effects of drug abuse begin with abusers and their families. Substance abuse has been a factor in divorce, family violence and related problems. The social effects extend into the larger society, as well, such as through crimes committed by drug abusers to get money needed to feed drug habits. Further, the lucrative nature of drug trafficking fuels crime as rival drug gangs fight for control of the traffic. The U.S. government, for example, noted increased drug-related violence on the U.S.-Mexico border and cited drug gangs in these areas as the nation's leading organised crime threat.
Reports by UNDCP have pointed out that the economic effects of drug abuse can be measured in two forms. One is the cost of government drug enforcement policies. Nations around the world spend billions yearly on law enforcement and other efforts aimed at drug interdiction. Because a central principle in economics is that resources are scarce and require decisions about how to allocate them, it follows that money spent on drug enforcement is money not spent on education, public infrastructure, or given to the public in the form of lower taxes. Another economic effect from drug abuse is the lost human productivity, such as lost wages and decreased production that results from illnesses and premature deaths related to drug abuse.
The economic effect of drug abuse varies across countries, according to UNDCP, which cited some individual nations as specific examples in its reports. In Canada, for example, UNDCP estimated that lost productivity related to drug abuse accounted for 60 per cent of the economic effect of drug abuse there. Estimates for Germany indicated that drug abuse, drug enforcement and treatment costs nearly £6 billion per year, half of which stemmed from lost productivity resulting from illness and premature deaths.
UNDCP stated that its estimates of the social and economic effects of drug abuse do not include costs resulting from crimes committed by drug abusers to get money to finance habits.