Drug Addiction (Substance Use Disorder)

What addiction does to the brain

Drugs activate the brain's reward system, releasing dopamine in amounts and speeds that natural rewards do not match. With repeated use:

• the reward system adapts, so everyday pleasures feel flat and more drug is needed for the same effect (tolerance)
• stress circuits become overactive, so stopping causes anxiety, irritability and low mood (withdrawal)
• the prefrontal cortex, which governs judgment and self-control, works less effectively, making it harder to resist cravings

This is why addiction is considered a medical condition, not a moral failing or lack of willpower. These brain changes can partly reverse with sustained recovery.

Signs of drug addiction

Doctors diagnose substance use disorder using 11 criteria. Having 2 or 3 in a year indicates mild, 4 or 5 moderate, and 6 or more severe disorder:

1. using more, or for longer, than intended
2. wanting or trying to cut down without success
3. spending a lot of time getting, using or recovering from the drug
4. cravings
5. failing to meet obligations at work, school or home
6. continuing despite relationship problems
7. giving up important activities
8. using in physically dangerous situations
9. continuing despite physical or mental health problems
10. tolerance
11. withdrawal

What others may notice

• changes in mood, sleep, appetite and weight
• secrecy, lying or stealing, money problems
• new friends or withdrawal from family
• declining performance at work or school
• bloodshot eyes, small or large pupils, track marks, nosebleeds
• drug paraphernalia

Causes and risk factors

• Genetics: account for roughly 40 to 60 percent of the risk.
• Early use: starting in adolescence, when the brain is still developing, greatly raises risk.
• Trauma and adverse childhood experiences.
• Mental health conditions: depression, anxiety, PTSD, ADHD and bipolar disorder often coexist.
• Environment: family substance use, peer use, availability, poverty and stress.
• The drug itself: fast-acting drugs and injecting or smoking increase addiction potential.
• Prescribed medicines: opioids or sedatives taken long-term can lead to dependence and, in some, addiction.

Common types of substance use disorder

See opioid use disorder, alcohol use disorder and stimulant use disorder.

Withdrawal

Withdrawal symptoms depend on the drug. Opioid withdrawal is extremely unpleasant (aches, diarrhea, sweating, anxiety, cravings) but rarely life-threatening in healthy adults. Alcohol and benzodiazepine withdrawal can cause seizures and delirium and can be fatal, so stopping after heavy use should be medically supervised. See drug withdrawal.

Treatment

Treatment is tailored to the person and substance, and works best when it continues long term, like care for other chronic conditions.

Medicines

• For opioid use disorder: buprenorphine and methadone reduce cravings and withdrawal and cut the risk of overdose death roughly in half. Extended-release naltrexone blocks opioid effects after detox. Buprenorphine can be prescribed by many clinicians in primary care.
• For alcohol use disorder: naltrexone, acamprosate and disulfiram.
• For nicotine: replacement therapy, varenicline and bupropion.

Behavioral therapies

• cognitive behavioral therapy (CBT)
• contingency management (rewards for drug-free tests), particularly effective for stimulants
• motivational interviewing
• family therapy, especially for teenagers

Levels of care

Outpatient programs, intensive outpatient and partial hospitalization, residential treatment, and medically managed detox, depending on need.

Peer and community support

Mutual help groups (12-step, SMART Recovery), peer recovery coaches and recovery housing.

Harm reduction

Carry naloxone, never use alone, use fentanyl test strips, use sterile equipment from syringe services programs, and get tested for HIV and hepatitis C. These steps save lives and connect people to treatment.

How to help someone with addiction

• Talk calmly when they are sober; express concern with specific examples, without blame.
• Learn about treatment options and offer to help find care.
• Keep naloxone at home if opioids are involved.
• Set boundaries and look after your own wellbeing; family support groups help.
• Recognize that relapse can be part of recovery, not a reason to give up.

Outlook

Addiction is a chronic condition, and relapse rates are similar to those of other chronic illnesses such as asthma and high blood pressure. Many people achieve long-term recovery, especially with medication when available and ongoing support.

Frequently asked questions

What are the signs of drug addiction?

Signs include cravings, using more than intended, failed attempts to cut down, spending lots of time on drug use, neglecting responsibilities, giving up activities, using despite harm, tolerance and withdrawal. Others may notice mood changes, secrecy, money problems and changes in sleep or weight.

Is addiction a disease?

Yes. Major medical organizations recognize substance use disorder as a chronic brain condition. Repeated drug use changes brain circuits for reward, stress and self-control, which makes stopping difficult. Like other chronic conditions, it responds to treatment and can be managed long term.

What is the most effective treatment for drug addiction?

It depends on the drug. For opioid use disorder, medicines such as buprenorphine and methadone are the most effective treatment and reduce overdose deaths. For other drugs, behavioral therapies such as CBT and contingency management are central. Combining medicine, therapy and support works best.

Can you recover from addiction on your own?

Some people do, but many need help, and support improves the chances of lasting recovery. Stopping alcohol or sedatives suddenly after heavy use can be dangerous. Talk to a doctor or call the SAMHSA National Helpline at 1-800-662-4357 to find treatment.

How can I tell if someone is overdosing?

Signs of an opioid overdose include unresponsiveness, slow or stopped breathing, gurgling or snoring sounds, pinpoint pupils and blue lips. Call 911, give naloxone if available, and start rescue breathing or CPR. Stimulant overdose causes chest pain, overheating, seizures or severe agitation.