Substance use disorder

The exact cause of substance use disorder is not known. A person's genes, the action of the prescribed medicine or illegal drug, peer pressure, emotional distress, anxiety, depression, and environmental stress can all be factors.

Many who develop a substance use problem have depression, attention deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), or another mental health issue. A stressful or chaotic lifestyle and low self-esteem are also common.

Children who grow up seeing their parents misuse substances may have a high risk of developing substance use problem later in life for both environmental and genetic reasons.

Commonly used substances include:

• Opiates and other narcotics are powerful painkillers that can cause drowsiness, and sometimes intense feelings of well-being, elation, happiness, excitement, and joy. These include heroin, opium, codeine, and narcotic pain medicines that may be prescribed by a health care provider or acquired illegally.
• Stimulants are substances that stimulate the brain and nervous system. They include cocaine, amphetamines, and some medicines used to treat ADHD (such as methylphenidate, or Ritalin). A person can start needing higher amounts of these substances over time to feel the same effect.
• Depressants cause drowsiness and reduce anxiety. They include alcohol, barbiturates, benzodiazepines (Valium, Ativan, Xanax), chloral hydrate, and paraldehyde. Using these substances can lead to addiction.
• LSD, mescaline, psilocybin ("mushrooms"), and phencyclidine (PCP, or "angel dust") can cause a person to see things that are not there (hallucinations) and can lead to psychological addiction.
• Marijuana (cannabis, or hashish).

There are several stages of substance use that may lead to addiction. Young people seem to move more quickly through the stages than do adults. Stages are:

• 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 at school or work; worries about losing substance supplier; uses substances 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 substance.
• Problem or risky use -- The user loses any motivation; does not care about school and work; has obvious behavior changes; thinking about substance use is more important than all other interests, including relationships; the user becomes secretive; may begin dealing substances to help support habit; use of other, harder substances may increase; legal problems may increase.
• Addiction -- Cannot face daily life without substance; 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.

Symptoms and behaviors of substance use may include:

Drug tests (toxicology screens) on blood and urine samples can show many chemicals and substances in the body. How sensitive the test is depends on the substance itself, when the substance was used, and the testing laboratory. Blood tests are more likely to find a substance than urine tests, though urine substance screens are done more often.

Substance use disorder is a serious condition and not easy to treat. The best care and treatment involve trained professionals.

Treatment begins with recognizing the problem. Though denial is a common symptom of addiction, people who are addicted have far less denial if they are treated with empathy and respect, rather than told what to do or being confronted.

The substance may either be slowly withdrawn or stopped abruptly. Support for physical and emotional symptoms, as well as staying substance free (abstinence) are also key to treatment.

• People with substance overdose may need emergency treatment in the hospital. The exact treatment depends on the drug used.
• Detoxification (detox) is the withdrawal of the substance abruptly in an environment where there is good support. Detoxification can be done on an inpatient or outpatient basis.
• At times, another substance with a similar action or effect on the body is taken, as the dose is slowly decreased to reduce the side effects and risks of withdrawal. For example, for narcotic addiction, methadone or similar medicines may be used to prevent withdrawal and continued use.

Residential treatment programs and intensive outpatient programs monitor and address possible withdrawal symptoms and behaviors. These programs use techniques to get users to recognize their behaviors and learn how not to go back to using (relapse).

If the person also has depression or another mental health issues, it should be treated. In many cases, a person starts using substances to try to self-treat mental health illness.

Many support groups are available in the community. They include:

• Narcotics Anonymous (NA) -- www.na.org
• Alateen -- al-anon.org/for-members/group-resources/alateen/
• Al-Anon -- al-anon.org

Most of these groups follow the 12-Step program used in Alcoholics Anonymous (AA) www.aa.org.

SMART Recovery www.smartrecovery.org and Life Ring Secular Recovery www.lifering.org are programs that do not use the 12-step approach. You can find other support groups on the Internet.

Substance use may lead to a fatal overdose. Some people start taking the substances again (relapse) after they have stopped.

Complications of substance use include:

• Depression
• Cancer, for example, mouth and stomach cancer are linked to alcohol use and dependence
• Infection with HIV, or hepatitis B or C through shared needles
• Loss of job
• Problems with memory and concentration, for example, hallucinogen use, including marijuana (THC)
• Problems with the law
• Relationship breakup
• Unsafe sexual practices, which may result in unwanted pregnancies, sexually transmitted diseases, HIV, or viral hepatitis

Make an appointment with your provider if you or a family member is using a substance and wants to stop. Also contact your provider if you have been cut off from your drug supply and are at risk of withdrawal. Most employers offer referral services for their employees with substance use problems.

If you or someone you know is thinking about suicide, call or text 988 or chat 988lifeline.org. You can also call 1-800-273-8255 (1-800-273-TALK). The 988 Suicide and Crisis Lifeline provides free and confidential support 24/7, anytime day or night.

You can also call 911 or the local emergency number or go to the hospital emergency room. DO NOT delay.

If someone you know has attempted suicide, call 911 or the local emergency number right away. DO NOT leave the person alone, even after you have called for help.

Substance education programs can be helpful. Parents can have a strong influence on their children by teaching them about the harm of using substances.

Substance misuse; Chemical use; Chemical misuse; Drug addiction; Addiction - drug; Dependence on drugs; Illicit drug use; Narcotic use; Hallucinogen use

American Psychiatric Association website. Substance-related and additive disorders. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Text Revision (DSM-5-TR), Washington, DC: American Psychiatric Association Publishing; 2022.

Breuner CC. Substance use disorder. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 157.

Kowalchuk A, Reed BC. Substance use disorders. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 50.

Weiss RD, Liebschutz JM. Drug use disorders. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 365.

Updated by: Fred K. Berger, MD, addiction and forensic psychiatrist, Scripps Memorial Hospital, La Jolla, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.