Drug dependence means that a person needs a drug to function normally. Abruptly stopping the drug leads to withdrawal symptoms. Drug addiction is the compulsive use of a substance, despite its negative or dangerous effects.
A person may have a physical dependence on a substance without having an addiction. For example, certain blood pressure medications do not cause addiction but they can cause physical dependence. Other drugs, such as cocaine, cause addiction without leading to physical dependence.
Tolerance to a drug (needing a higher dose to attain the same effect) is usually part of addiction.
Drug addiction; Addiction - drug; Dependence on drugs
Causes, incidence, and risk factors
Drug abuse can lead to drug dependence or addiction. People who use drugs for pain relief may become dependent, although this is rare in those who don't have a history of addiction.
The exact cause of drug abuse and dependence is not known. However, a person's genes, the action of the drug, peer pressure, emotional distress, anxiety, depression, and environmental stress all can be factors.
Peer pressure can lead to drug use or abuse, but at least half of those who become addicted have depression, attention deficit disorder, post-traumatic stress disorder, or another mental health problem.
Children who grow up in an environment of illicit drug use may first see their parents using drugs. This may put them at a higher risk for developing an addiction later in life for both environmental and genetic reasons.
People who are more likely to abuse or become dependent on drugs include those who:
Have depression, bipolar disorder, anxiety disorders, and schizophrenia
Have easy access to drugs
Have low self-esteem, or problems with relationships
Live a stressful lifestyle, economic or emotional
Live in a culture where there is a high social acceptance of drug use
Commonly abused substances include:
Opiates and narcotics are powerful painkillers that cause drowsiness (sedation) and sometimes feelings of euphoria. These include heroin, opium, codeine, meperidine (Demerol), hydromorphone (Dilaudid), and oxycodone (Oxycontin).
Central nervous system (CNS) stimulants include amphetamines, cocaine, dextroamphetamine, methamphetamine, and methylphenidate (Ritalin). These drugs have a stimulating effect, and people can start needing higher amounts of these drugs to feel the same effect (tolerance).
Central nervous system depressants include alcohol, barbiturates (amobarbital, pentobarbital, secobarbital), benzodiazepines (Valium, Ativan, Xanax), chloral hydrate, and paraldehyde. These substances produce a sedative and anxiety-reducing effect, which can lead to dependence.
Hallucinogens include LSD, mescaline, psilocybin ("mushrooms"), and phencyclidine (PCP or "angel dust"). They can cause people to see things that aren't there (hallucinations) and can lead to psychological dependence.
Tetrahydrocannabinol (THC) is the active ingredient found in marijuana (cannabis) and hashish.
There are several stages of drug use that may lead to dependence. Young people seem to move more quickly through the stages than do adults.
Experimental use -- typically involves peers, done for recreational use; the user may enjoy defying parents or other authority figures.
Regular use -- the user misses more and more school or work; worries about losing drug source; uses drugs to "fix" negative feelings; begins to stay away from friends and family; may change friends to those who are regular users; shows increased tolerance and ability to "handle" the drug.
Daily preoccupation -- the user loses any motivation; does not care about school and work; has obvious behavior changes; thinking about drug use is more important than all other interests, including relationships; the user becomes secretive; may begin dealing drugs to help support habit; use of other, harder drugs may increase; legal problems may increase.
Dependence -- cannot face daily life without drugs; denies problem; physical condition gets worse; loss of "control" over use; may become suicidal; financial and legal problems get worse; may have broken ties with family members or friends.
Some of the symptoms and behaviors of drug dependence include:
Continuing to use drugs even when health, work, or family are being harmed
Episodes of violence
Hostility when confronted about drug dependence
Lack of control over drug abuse - being unable to stop or reduce alcohol intake
Making excuses to use drugs
Missing work or school, or a decrease in performance
Need for daily or regular drug use to function
Neglecting to eat
Not caring for physical appearance
No longer taking part in activities because of drug abuse
Secretive behavior to hide drug use
Using drugs even when alone
See: Drug abuse for more information about symptoms that may be present when using these drugs.
For information about symptoms of withdrawal, see also:
Drug tests (toxicology screens) on blood and urine samples can show many chemicals and drugs in the body. How sensitive the test is depends upon the drug itself, when the drug was taken, and the testing laboratory. Blood tests are more likely to find a drug than urine tests. However, urine drug screens are done more often.
Opiates and narcotics are usually in the urine 12 to 36 hours after the last use, depending on the amount used and how often the drug was used.
CNS stimulants such as cocaine can be found in urine for 1 to 12 days, again depending on how often the drug was used.
CNS depressants such as Valium and Xanax are found up to 7 days after the last day of use, mostly depending on the substance used and how quickly the body removes it (its half-life).
Most hallucinogens also can be found in the urine up to 7 days after the last use. However, evidence of marijuana can be found for up to 28 days after its last use in regular users.
Treatment for drug abuse or dependence begins with recognizing the problem. Though "denial" used to be considered a symptom of addiction, recent research has shown that people who are addicted have far less denial if they are treated with empathy and respect, rather than told what to do or "confronted."
Treatment of drug dependency involves stopping drug use either gradually or abruptly (detoxification), support, and staying drug free (abstinence).
People with acute intoxication or drug overdose may need emergency treatment. Sometimes, the person loses consciousness and might need to be on a breathing machine (mechanical respirator) temporarily. The treatment depends on the drug being used.
Detoxification is the withdrawal of an abused substance in a controlled environment. Sometimes a drug with a similar action is taken instead, to reduce the side effects and risks of withdrawal. Detoxification can be done on an inpatient or outpatient basis.
As with any other area of medicine, the least intensive treatment should be the starting point.
Residential treatment programs monitor and address possible withdrawal symptoms and behaviors. These programs use behavior modification techniques, which are designed to get users to recognize their behaviors.
Treatment programs include counseling, both for the person (and perhaps family), and in group settings. Drug abuse treatment programs have a long after-care part (when the user is released from the medical facility), and provide peer support.
Drug addiction is a serious and complicated health condition that requires both physical and psycholocial treatment and support. It is important to be evaluated by a trained professional to determine the best care.
If the person also has depression or another mood disorder, it should be treated. Very often, people start abusing drugs in their effort to self-treat mental illness.
For narcotic dependence, some people are treated with methadone or similar drugs to prevent withdrawal and abuse. The goal is to enable the person to live as normal a life as possible.
Many support groups are available in the community. They include Narcotics Anonymous (NA), Ala-Teen, and Al-Anon. Most of these groups follow the 12-Step program used in Alcoholics Anonymous (AA). SMART Recovery and LifeRing Recovery are programs that do not use the 12-step approach. You can find support groups in your phone book.
Drug abuse and dependence may lead to a fatal drug overdose. Some people start taking the drugs again after they have stopped. Relapses can lead to continued dependence.
The complications of drug abuse and dependence include:
Increase in various cancer rates; for example, lung and pharynx cancer are linked to nicotine use; mouth and stomach cancer are associated with alcohol abuse and dependence
Infection with HIV through shared needles
Problems with memory and concentration, for example with hallucinogen use, including marijuana (THC)
Problems with the law
Relapse of drug abuse
Unsafe sexual practices, which may result in unwanted pregnancies, sexually transmitted diseases, HIV, or hepatitis
Calling your health care provider
Call for an appointment with your health care provider if you are addicted to drugs and would like to get off of them, or if you have been cut off from your drug supply and are at risk of withdrawal. Most employers also offer referral services for their employees with substance abuse problems.
Drug education programs may be helpful though none has proved effective in the long term.
Kleber HD, Weiss Rd, Anton RF, George TP, Greenfield SF, Kosten TR, et al. Treatment of patients with substance use disorders. Am J Psychiatry. 2007;164:5-123.
Griswold KS, Atronoff H, Kernan JB, Kahn LS. Adolescent substance use and abuse: recognition and management. Am Fam Physician. 2008;77:331-336.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.