Diagnosis
DSM classification
"Substance dependence", as defined in the DSM-IV, can be diagnosed with physiological dependence, evidence of tolerance or withdrawal, or without physiological dependence. DSM-IV substance dependencies include:

303.90 Alcohol dependence
304.00 Opioid dependence
304.10 Sedative, hypnotic, or anxiolytic dependence (including benzodiazepine dependence and barbiturate dependence)
304.20 Cocaine dependence
304.30 Cannabis dependence
304.40 Amphetamine dependence (or amphetamine-like)
304.50 Hallucinogen dependence
304.60 Inhalant dependence
304.80 Polysubstance dependence
304.90 Phencyclidine (or phencyclidine-like) dependence
304.90 Other (or unknown) substance dependence
305.10 Nicotine dependence

Management
Addiction is a complex but treatable condition. It is characterized by compulsive drug craving, seeking, and use that persists even if the user is aware of severe adverse consequences. For some people, addiction becomes chronic, with periodic relapses even after long periods of abstinence. As a chronic, relapsing disease, addiction may require continued treatments to increase the intervals between relapses and diminish their intensity. While some with substance issues recover and lead fulfilling lives, others require ongoing additional support. The ultimate goal of addiction treatment is to enable an individual to manage their substance misuse; for some this may mean abstinence. Immediate goals are often to reduce substance abuse, improve the patients ability to function, and minimize the medical and social complications of substance abuse and their addiction; this is called "harm reduction". Treatments for addiction vary widely according to the types of drugs involved, amount of drugs used, duration of the drug addiction, medical complications and the social needs of the individual.
Most countries have legislation which brings various drugs and drug-like substances under the control of licensing systems. Typically this legislation covers any or all of the opiates, amphetamines, cannabinoids, cocaine, barbiturates, benzodiazepines, anesthetics, hallucinogenics, derivatives and a variety of more modern synthetic drugs. Unlicensed production, supply or possession is a criminal offence. Usually, however, drug classification under such legislation is not related simply to addictiveness. The substances covered often have very different addictive properties. Some are highly prone to cause physical dependency, while others rarely cause any form of compulsive need whatsoever. Also, under legislation specifically about drugs, alcohol and nicotine are not usually included.Although the legislation may be justifiable on moral or public health grounds, it can make addiction or dependency a much more serious issue for the individual: reliable supplies of a drug become difficult to secure, and the individual becomes vulnerable to both criminal abuse and legal punishment. It is unclear whether laws against illegal drug use do anything to stem usage and dependency. In jurisdictions where addictive drugs are illegal, they are generally supplied by drug dealers, who are often involved with organized crime. Even though the cost of producing most illegal addictive substances is very low, their illegality combined with the addicts need permits the seller to command a premium price, often hundreds of times the production cost. As a result, addicts sometimes turn to crime to support their habit. United States
In the United States, drug policy is primarily controlled by the federal government.