Drug Addiction Health Center

Drug abuse and addiction, broadly, refers to the ingestion of a substance that has psychoactive effects by altering the balance of chemicals in the brain. Typically, people might associate the term 'drug addiction' with street drugs, such as heroin, cocaine, methamphetamine and marijuana. However, many more people are addicted to legal drugs such as alcohol, tobacco, and prescription medications.

Drug addiction, or more broadly, substance addiction, is a problem that goes back centuries in civilization. When someone is dependent on a substance, that means that they need the substance to function normally, and stopping taking it all of a sudden will cause withdrawal symptoms. Drug addiction on the other hand, means that someone compulsively uses the substance despite the negative or dangerous effects that result from it's use. Most addicts are dependent on their substance, but not all dependent persons are addicted. As someone continues to use or abuse the substance, they can develop tolerance to the substance, meaning more and more of it is needed to achieve the same effect.

The cause of drug addiction is not known, however the interplay between a person's genes, environment, upbringing, and mental health all play a role in whether someone becomes addicted to a substance. People who have mental health problems and who are under emotional stress, or suffering with depression or anxiety are at greater risk for drug addiction, as are people who have family histories of addiction. The National Institutes of health notes that the people who are most likely to abuse or become addicted to drugs include people 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:

  • 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. 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 such as 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 such as 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.

Marijuana Use

The 2009 National Survey on Drug Use and Health reported that 16.7 million Americans aged 12 or older used marijuana at least once in the month prior to being surveyed, and it is the most used illegal drug in the United States. It is cultivated from the buds and flowers of the plant Cannabis sativa, and is most commonly smoked as a cigarette or in a pipe to achieve the short-term psychoactive effects of euphoria, altered consciousness, and many others.

Short term physiological effects include increased heart-rate, dry mouth, red eyes, and muscle relaxation. Negatively, marijuana use can cause distorted perceptions, impaired coordination, difficulty with thinking and problem solving, and problems with learning and memory.

Long-term marijuana users who are trying to quit report withdrawal symptoms including irritability, sleeplessness, decreased appetite, anxiety, and drug craving. Long term health risks of marijuana use include the same respiratory problems as tobacco smokers, such as daily cough and phlegm production, more frequent acute chest illness, and a heightened risk of lung infections. Several studies have confirmed a correlation between long term use and anxiety, psychosis, and depression.

Social problems from marijuana abuse include increase mental health issues, and deficits in cognitive abilities, social life, and career status. Marijuana use for medicinal purposes has been the subject of much study and debate, as the active ingredients in marijuana have therapeutic potential for relieving pain, controlling nausea, stimulating appetite, and decreasing ocular pressure. Many states have medical marijuana programs where patients can access legal marijuana with a doctor's prescription.


It is estimated that approximately 1 million people in the United States suffer from heroin addiction, and another 1.4 million abuse prescription painkillers such as vicodin, oxycontin, and fentanyl. Opiates, derived from morphine, have been used as painkillers for centuries.

In the presence of chronic pain, users can become quickly addicted to them, as consistent use causes the body to stop making it's own natural painkillers, called endorphins. When an addict tries to stop using , the resulting withdrawal sickness causes vomiting, insomnia, digestive problems, anxiety, depression, and body aches; and often causes the addict to use again, to alleviate the withdrawal sickness. Overdose can cause respiratory depression and death.

Treatment is achieved with inpatient rehabilitation if possible, along with medications that can help alleviate withdrawal symptoms, such as methadone, Suboxone, Revia, and Subutex. Twelve step addiction recovery (Narcotics Anonymous) is also helpful for maintaining sobriety.

Review Date: 
March 13, 2012
Last Updated:
November 14, 2013