Change drug addiction and drug abuse, habitual use of a chemical in the body or statements of opinion, for purposes other than medically justified. Psychological dependence is the subjective feeling that the user needs the drug to a sense of wellbeing, physical dependence characterized by tolerance and withdrawal symptoms when the user is defending sober. Definitions of addiction are subjective and the infusion of moral principles of society or culture, the stimulant caffeine in coffee and tea is a drug for millions of people around the world, but because of its relatively mild stimulant effect and because caffeine does not activate the general antisocial behavior in people with these, is the consumption of tea and coffee, although physically addicted to caffeine, in general, rather than abuse. Corrosive used in the Indian subcontinent, opium for centuries without excessive demands on the social fabric. In comparison, 72% of the U.S. population has smoked cigarettes and 82% have tried alcohol. In addition, marijuana is the illegal substance most commonly used drug. Drug users, the experience of a variety of physical effects other cause of expectations. Some medications, such as marijuana and alcohol interfere with motor control and are factors in many automobile accidents. Users of drugs like marijuana and hallucinogenic drugs may experience flashbacks, unwanted repetitions of the effects of the drug weeks or months after use. The sudden withdrawal of some drugs resulted in the elimination of symptoms. For example, heroin and other drugs can remove vomiting, muscle cramps, convulsions and delirium. With continued use of a physically addictive drug, tolerance develops, becoming more and more amount of drug needed to double the initial impact itself. Exchange of syringes used to inject some drugs dramatically increases the risk of contracting HIV / AIDS. In addition, increased sexual activity among drug users, both prostitution and the disinheritance of some drugs, also provide a higher risk of AIDS and other STDs (sexually transmitted diseases). Due to the purity and amount of uncontrolled illegal drugs, drug overdose is a constant danger. The money to buy drugs and some medications, especially alcohol, are associated with violent behavior in users. There are over 15,000 deaths directly to drug use in the United States each year, most substances that participate regularly, cocaine, heroin, often in combination with alcohol or other drugs combined. Many drug users in relation to a crime such as prostitution, to raise the money to buy drugs, and drugs, in the case of alcohol, associated with violent behavior. Drug abuse affects society in many ways, the lifestyle. In the workplace, which is expensive in terms of lost work time and inefficiency. Drug users are more likely than nonusers to have to work, accidents, danger to himself and those around them. More than half of all road deaths in the United States of America in relation to alcohol. Drug-related crime can disrupt neighborhoods through violence among drug dealers, threats to residents and the crimes of the addicts. In some areas, children have been recruited as lookouts and helpers because of the low penalties for offenders, and firearms have been in children and adolescents on the agenda. The vast majority of homeless people have either a drug or alcohol problem or mental illness, many of the three.