What Is a Substance Use Disorder? Signs, Stages and When to Seek Help

If you or someone you know is in crisis right now: call or text 988 (Suicide & Crisis Lifeline). For a possible overdose or any medical emergency, call 911. For help finding treatment, the SAMHSA National Helpline is free and open 24/7 at 1-800-662-4357.

The short answer

A substance use disorder (SUD) is a medical condition in which a person keeps using alcohol or drugs even though it is causing harm to their health, relationships, work or safety. It ranges from mild to severe, and it is treatable at every level.

What is a substance use disorder?

A substance use disorder is a diagnosis used by doctors and mental health professionals. It describes a pattern of substance use that becomes hard to control and starts to interfere with daily life.

You will also hear the word addiction. In everyday language, addiction usually means the most severe form of a substance use disorder. Medical guidelines use “substance use disorder” because it covers the whole spectrum, from mild to severe.

A substance use disorder can involve alcohol, cannabis (marijuana), opioids, stimulants such as cocaine or methamphetamine, sedatives and sleep medications, tobacco, and other substances.

Using a substance does not automatically mean someone has a disorder. Many people drink alcohol or take prescribed medication without developing one. The difference is loss of control and continued use despite harm.

How common is it?

More common than most people think. SAMHSA’s 2024 National Survey on Drug Use and Health estimated that about 48.4 million Americans ages 12 and older, roughly 1 in 6, had a substance use disorder in the past year. Of those, 27.9 million had an alcohol use disorder and 28.2 million had a drug use disorder, and some people had both. samhsa samhsa

The treatment gap is large. About 52.6 million people needed substance use treatment in 2024, but only around 10.2 million, about 1 in 5, received any. If you are struggling, you are far from alone, and help is more available than it may feel. addictionpolicy

Signs and symptoms of a substance use disorder

Doctors use 11 criteria from the DSM-5, the standard diagnostic manual published by the American Psychiatric Association. They fall into four groups.

Loss of control

Using more, or for longer, than you meant to.
Wanting to cut down or stop, but not being able to.
Spending a lot of time getting the substance, using it or recovering from it.
Strong cravings or urges to use.

Problems at home, work or in relationships
5. Not meeting responsibilities at work, school or home because of use.
6. Continuing to use even though it causes problems with family or friends.
7. Giving up or cutting back on activities you used to enjoy.

Risky use
8. Using in situations that are physically dangerous, such as driving.
9. Continuing to use even though it is clearly harming your physical or mental health.

Physical dependence
10. Tolerance: needing more of the substance to get the same effect.
11. Withdrawal: physical or emotional symptoms when you cut down or stop.

Tolerance and withdrawal do not count toward a diagnosis when someone takes a medication exactly as prescribed under a doctor’s supervision.

How severity is measured

2-3 criteria: mild
4-5 criteria: moderate
6 or more criteria: severe

Only a qualified health professional can diagnose a substance use disorder. This list is meant to help you recognize patterns, not to diagnose yourself or someone else.

Warning signs you may notice in someone else

Family members are often the first to notice changes. Common signs include:

Changes in sleep, appetite, weight or appearance
Mood swings, irritability or withdrawal from loved ones
Secrecy, lying about where they have been or what they are doing
Missing work or school, or a drop in performance
Money problems or unexplained requests for cash
Losing interest in hobbies and friends
New legal or driving problems

These signs can also point to other health or life problems, so avoid jumping to conclusions. They are a reason to start a caring conversation, not a verdict.

The stages of a substance use disorder

There is no single official staging system, and not everyone moves through each step. Many professionals use a simple model to explain how substance use can progress. Treat it as a teaching tool, not a diagnosis.

1. Experimentation. Someone tries a substance, often out of curiosity, social pressure or a wish to feel better. Most people who try a substance do not go on to develop a disorder.

2. Regular use. Use becomes a habit or routine, such as drinking every weekend or taking a substance to cope with stress. Problems may not be obvious yet.

3. Risky use. Use starts to cause problems: missed obligations, risky decisions, arguments with loved ones. The person may start to hide it or minimize it.

4. Dependence. The body adapts. Tolerance grows and stopping brings withdrawal symptoms, which can make quitting feel impossible without help.

5. Addiction (severe disorder). Using becomes compulsive. The person keeps using despite serious consequences, and cravings and the brain’s changed response to reward make stopping very hard.

Recovery is not a final stage that arrives at a set point. It is an ongoing process, and setbacks are common and treatable. People can and do recover at every stage, though getting help earlier usually makes treatment easier and less disruptive.

What causes a substance use disorder?

There is no single cause. Risk comes from a mix of factors:

Genetics. Researchers estimate that genes account for roughly 40 to 60 percent of a person’s vulnerability.
Environment. Family, peers, stress, trauma, easy access to substances and community conditions all play a part.
Age of first use. Starting in adolescence, while the brain is still developing, raises the risk.
Mental health conditions. Depression, anxiety, PTSD and ADHD often occur alongside substance use disorders.
Substance type and how it is used. Some substances, such as opioids, and some methods of use carry a higher risk of dependence.

None of this means a substance use disorder is a character flaw or a lack of willpower. It is a health condition that affects the brain’s systems for motivation, reward and self-control.

When to seek help

You do not need to hit “rock bottom” before asking for help. Consider reaching out if:

You recognize two or more of the signs above in yourself.
You have tried to cut down or stop and could not.
Substance use is affecting your health, job, finances, safety or relationships.
A loved one, friend or doctor has expressed concern.
You are using a substance to cope with stress, pain, sleep or difficult emotions.

Get urgent medical help if:

Someone may have overdosed. Signs include being unresponsive, very slow or stopped breathing, blue or gray lips or fingertips, or gurgling sounds. Call 911 right away.
Withdrawal is severe. Seizures, hallucinations, severe confusion, a racing heart or high fever are medical emergencies. Withdrawal from alcohol and from benzodiazepines can be life-threatening.
There are thoughts of suicide or self-harm. Call or text 988.

Do not stop drinking alcohol or taking benzodiazepines suddenly on your own if you have been using heavily or for a long time. Talk to a doctor first so withdrawal can be managed safely.

What treatment looks like

Substance use disorders are treatable. Care is matched to the person and may include:

Behavioral therapies, such as cognitive behavioral therapy (CBT), that help change thinking and behavior patterns
Medications, available for alcohol, opioid and tobacco use disorders
Medically supervised detox, when withdrawal could be dangerous
Inpatient or outpatient programs, with different levels of support
Peer support, such as 12-step and other mutual-help groups
Treatment for co-occurring mental health conditions

Learn more: [Inpatient vs Outpatient Rehab: Which Level of Care Is Right for You?] · [Medication-Assisted Treatment (MAT): How It Works and Who It’s For] · [Does Insurance Cover Rehab?]

How to take the first step

Talk to a doctor you trust. A primary care provider can screen you, discuss options and refer you.
Call the SAMHSA National Helpline at 1-800-662-4357 for free referrals to local treatment and support.
Search FindTreatment.gov, the government’s locator for licensed treatment providers.
Check your insurance benefits. Many plans cover treatment. See our guide: [How to Find a Legitimate Rehab Center: Accreditation and Red Flags].
Tell one person. A friend, family member or counselor can help you follow through.

If you are worried about a loved one

Lead with care, not blame. Choose a calm moment, describe what you have noticed, and offer to help them find support. You cannot force someone to change, but your support matters. Family support groups such as Al-Anon and Nar-Anon can help you too.

Frequently asked questions

Is substance use disorder the same as addiction?
Mostly, yes. “Addiction” usually refers to the severe end of the spectrum. “Substance use disorder” is the clinical term and includes mild, moderate and severe forms.

Can you have a substance use disorder without being physically dependent?
Yes. Physical dependence (tolerance and withdrawal) is only two of the 11 criteria. A person can meet the criteria through loss of control, risky use and problems in daily life.

Is a substance use disorder a choice or a moral failing?
No. Using a substance may start as a choice, but a substance use disorder involves changes in brain function, along with genetic, psychological and environmental factors. It is a medical condition.

Can a substance use disorder be treated?
Yes. Treatment works for many people, and relapse does not mean failure. Like other chronic conditions, it often needs long-term management and adjustments over time.

How is a substance use disorder diagnosed?
A doctor, psychologist, counselor or addiction specialist asks about your substance use and how it affects your life, then compares your answers to the DSM-5 criteria. There is no single blood test for it.

Sources

SAMHSA. 2024 National Survey on Drug Use and Health (NSDUH) Annual National Report. samhsa.gov/data/report/2024-nsduh-annual-national-report
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR).
National Institute on Drug Abuse (NIDA). Drug Misuse and Addiction and Genetics and Epigenetics of Addiction. nida.nih.gov
National Institute on Alcohol Abuse and Alcoholism (NIAAA). Understanding Alcohol Use Disorder. niaaa.nih.gov

This article is for general information only and is not medical advice. It does not replace a diagnosis or treatment from a qualified health professional.