Alcohol and Drug Misuse, Abuse, and Addiction
In 2024, an estimated one in five adults in the United States (48.7 million people) met the criteria for a substance use disorder.¹ If you are searching for answers about your own use or someone you care about, you are not alone, and this page is a place to start.
What is drug and alcohol addiction?
Drug and alcohol addiction, clinically called substance use disorder, or SUD, is a chronic medical condition in which a person continues to seek and use a substance despite serious harm to their health, relationships, or daily functioning. The American Psychiatric Association, the National Institute on Drug Abuse (NIDA), and the Substance Abuse and Mental Health Services Administration (SAMHSA) all classify SUD as a brain disease.² ³
Addiction is not a character flaw or a failure of willpower.
Addiction exists on a spectrum. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) rates its severity as mild, moderate, or severe based on the number of diagnostic criteria a person meets. “Addiction” in everyday language generally refers to the moderate-to-severe end of that spectrum, where use has become compulsive and where stopping (even when a person wants to) is genuinely difficult.
Alcohol use disorder (AUD) is the most common form of SUD in the United States, followed by cannabis use disorder and opioid use disorder (OUD).¹ Any substance that produces changes in the brain’s reward system carries some risk of disordered use.
SUD also commonly occurs alongside mental health conditions, because the two share overlapping brain pathways and each can worsen the other. Our guide to co-occurring disorders and dual diagnosis covers that connection in depth.
How does addiction develop?
Drug and alcohol addiction rarely appears overnight. It typically progresses through stages, and because the shift between stages can be gradual, many people do not recognize a problem until it is well established.
A common progression looks like this:
- Experimental or prescribed use: A person tries a substance for the first time, or begins taking a prescribed medication as directed.
- Regular use: Use becomes more frequent. Social or recreational use settles into a pattern.
- Heavy use: Use is routine, with few days off. Tolerance often develops during this stage.
- Substance use disorder: Use is daily or near-daily. The person has lost meaningful control over the amount or frequency, and attempts to cut back repeatedly fail.⁴
Two terms that often cause confusion are physical dependence and addiction.
Physical dependence is the body’s adaptation to a substance: when use stops or drops sharply, withdrawal symptoms appear. A person can be physically dependent on a medication prescribed by a doctor, such as an opioid for chronic pain, without meeting the clinical criteria for addiction.
Addiction adds compulsive use and continued use despite clear consequences. Both can occur at the same time, but they are distinct conditions.³
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How addiction affects the brain
When someone uses alcohol or drugs, the brain’s reward system releases a surge of dopamine, a chemical that signals pleasure and motivates repeated behavior.
This is a normal mechanism; it is how the brain reinforces eating, social connection, and other behaviors important for survival. Substances exploit that same system, producing dopamine releases far larger than any natural reward.⁵
But, over time, the brain responds to those artificial surges by reducing its own dopamine production and the sensitivity of dopamine receptors. The result is that ordinary pleasures feel flat and the substance starts to feel necessary just to feel normal. This is why cravings feel urgent, why stopping is physically and psychologically painful, and why relapse can happen years after a person has stopped using.
The prefrontal cortex (the brain region responsible for decision-making and impulse control) is also affected by sustained heavy use. This helps explain why a person with a SUD may continue to use even when they clearly recognize the costs. It is not that they do not understand what is happening to them; it is that the brain’s control mechanisms have been compromised by the very substance causing the harm.⁵
Recovery allows the brain to rebalance, but this takes time. Longer treatment and sustained support work partly because they give the brain the substance-free period it needs to begin that process.
For more on alcohol’s specific effects on brain chemistry, see our guides on alcohol and opioid addiction.
What are the signs of drug and alcohol addiction?
The DSM-5 identifies 11 diagnostic criteria for substance use disorder.⁶ A clinician evaluating someone for SUD looks at how many of the following applied in the previous 12 months:
Loss of control
- Using more of the substance, or for longer, than intended
- Repeated unsuccessful efforts to cut down or stop
- Spending a great deal of time obtaining, using, or recovering from the substance
- Experiencing persistent cravings or strong urges to use
Social and role impairment
- Failing to meet obligations at work, school, or home because of substance use
- Continuing to use despite persistent or recurring problems in relationships caused or worsened by use
- Giving up social, occupational, or recreational activities in order to use
Risky use
- Using in situations where doing so creates physical risk (such as driving)
- Continuing to use despite a known physical or psychological problem that is caused or worsened by the substance
Physical changes
- Tolerance: needing noticeably more of the substance to achieve the same effect
- Withdrawal: experiencing characteristic symptoms when use is reduced or stopped
Two to three criteria in 12 months indicates mild SUD. Four to five indicates moderate. Six or more indicates severe.⁶
Signs look different from person to person and substance to substance.
Someone with alcohol use disorder may primarily show behavioral changes such as missed obligations, relationship conflict, irritability when sober. Whereas someone with opioid use disorder may show more physical markers like withdrawal symptoms, substantially changed sleep, significant weight loss.
If you are concerned about your own use or a loved one’s, a clinical assessment is the most reliable path to an accurate picture.
What causes addiction? Risk factors and vulnerability
No single factor explains why one person develops a substance use disorder while another with similar exposure does not. Research consistently identifies three categories of risk:
Biology and genetics
Genetics account for approximately 40–60% of individual vulnerability to addiction, according to NIDA.⁵ Having a parent or sibling with a SUD raises statistical risk without determining outcomes. Variations in genes that regulate dopamine signaling and the stress response are among the biological mechanisms researchers have identified.
Environment
Early exposure to substances, trauma, chronic stress, childhood neglect or abuse, and easy access to drugs or alcohol all increase risk. Adverse childhood experiences (ACEs), including physical or emotional abuse, household substance use, and parental mental illness, have a measurable, cumulative relationship with the likelihood of later addiction.⁷ Limited access to mental health care and housing or economic instability also raise vulnerability.
Developmental timing
The earlier someone begins using a substance, the higher their risk. The adolescent brain is more susceptible to the rewiring effects of repeated substance exposure than the adult brain. People who begin using substances before age 18 are four to seven times more likely to develop a SUD than those who start in adulthood.⁵
Risk factors are not destiny.
Protective factors, such as stable family relationships, mental health support, strong social connection, and delayed onset of use, meaningfully reduce risk even when biological or environmental vulnerabilities are present.
Types of drug and alcohol addiction
Substance use disorders can develop with almost any psychoactive substance. The most prevalent in the United States include:
- Alcohol use disorder is the most common form of SUD, affecting an estimated 29.5 million adults in the U.S. in 2023.¹ Because alcohol is legal and socially normalized, the line between heavy use and disordered use is often crossed without recognition.
- Opioid use disorder, including prescription painkillers, heroin, and fentanyl, has driven the U.S. overdose crisis for more than two decades. Fentanyl, a synthetic opioid far more potent than morphine, is now involved in the majority of overdose deaths.⁸
- Stimulant use disorder covers cocaine, methamphetamine, and prescription stimulants such as Adderall. Methamphetamine use has increased substantially over the past decade.
- Cannabis use disorder affects an estimated 5.9 million adults annually in the U.S.¹ As potency has increased with higher-THC products, so has the rate of disordered use.
- Benzodiazepine and sedative use disorder (including medications such as Xanax, Valium, and Klonopin) carries particularly serious withdrawal risks that require medical supervision to manage safely.
- Hallucinogen use disorder is less common than other categories but does occur, including with MDMA and PCP.
- Behavioral addictions (gambling disorder being the most recognized) activate the same reward pathways as substance use and are classified in the DSM-5. No chemical substance is involved, but the loss-of-control pattern is similar.
Addiction and mental health
More than half of people with a substance use disorder also have a co-occurring mental health condition.¹ The most common pairings involve depression, anxiety disorders, PTSD, bipolar disorder, and ADHD, though any psychiatric condition can co-occur with SUD.
The relationship runs in both directions. Mental health conditions increase the risk of developing a SUD, often because substances temporarily relieve distressing symptoms. This pattern is a documented pathway into disordered use for many people. At the same time, sustained heavy use of alcohol or drugs can trigger or worsen depression, anxiety, psychosis, and other psychiatric conditions. By the time someone enters treatment, it is often difficult to establish which came first.
This is why clinicians use the term dual diagnosis to describe the combination. Treating only the substance use while leaving a mental health condition unaddressed (or vice versa) significantly reduces the likelihood of sustained recovery.⁹ Integrated treatment that addresses both conditions at the same time is the standard of evidence-based care.
Our dual diagnosis guide covers co-occurring conditions in detail, including depression and addiction, anxiety and alcohol or drug use, and PTSD and substance use disorder.
How addiction affects families
Addiction rarely stays contained to the person experiencing it. Partners, children, parents, and close friends are drawn into its effects — often carrying financial strain, emotional exhaustion, and relational damage that accumulates quietly over years.
Family members commonly develop responses to a loved one’s addiction that, over time, can make it easier for use to continue. Covering for missed responsibilities, providing money that goes toward substances, or consistently avoiding conflict around use are examples of enabling patterns, not because family members intend to cause harm, but because they are trying to manage a crisis with whatever tools they have available. Understanding where support ends and enabling begins is one of the most useful things a family member can learn.
Our guide to how addiction affects families covers family dynamics, enabling, and recovery support in more depth.
When a family member is unwilling to seek help on their own, a structured intervention, typically facilitated by a trained interventionist, can provide a focused opportunity for family and friends to express concern and present a concrete treatment option. See our guide to how to stage an intervention.
When is it time to get help?
If substance use is affecting your health, your relationships, your work, or your ability to function, and you have found it genuinely difficult to cut back on your own – that pattern is worth taking seriously with professional support.
Many people delay seeking help for years, often because they believe their situation is not severe enough, or that they should manage it without outside assistance. Substance use disorder is a medical condition. The expected response to a chronic medical condition is clinical support, and the evidence is consistent: earlier intervention leads to better outcomes.¹⁰ A person does not need to reach a crisis point to deserve care.
If you are ready to take a next step, the options are broader than most people expect. Treatment includes flexible outpatient programs built around work and family responsibilities, short-term inpatient stays, and medication-assisted treatment that substantially reduces cravings and withdrawal. Cost and insurance are common concerns; under the Affordable Care Act, most major insurance plans are required to cover substance use disorder treatment.
What does addiction treatment involve?
Effective treatment addresses more than substance use in isolation. The most widely supported approaches combine medical care, behavioral therapy, peer support, and attention to underlying mental health conditions.
The standard continuum of care includes several levels, and the appropriate starting point depends on the severity of the SUD and the person’s circumstances:
Medical detox is the supervised management of withdrawal, with medications to reduce discomfort and prevent dangerous complications. Detox is the necessary first step for people with significant physical dependence on alcohol, opioids, or benzodiazepines. It is not treatment on its own, but it makes treatment possible.
Inpatient or residential treatment provides 24-hour structured care, typically lasting 30, 60, or 90 days. It is the appropriate level for people with severe SUD, an unstable home environment, co-occurring medical needs, or prior treatment attempts that have not held.
Partial hospitalization (PHP) and intensive outpatient (IOP) are structured day programs that allow a person to return home in the evenings. PHP and IOP are common step-down options after residential care, and the primary route for many people who cannot take extended time away from work or family.
Standard outpatient involves weekly or twice-weekly therapy sessions. Appropriate for mild-to-moderate SUD with a stable home environment, and a common maintenance level after completing higher levels of care.
Medication-assisted treatment (MAT) uses FDA-approved medications to reduce cravings and withdrawal for opioid and alcohol use disorders. Methadone, buprenorphine (Suboxone), and naltrexone (Vivitrol) are among the most studied. MAT is a medical treatment that supports neurological stabilization while a person rebuilds their life — not a substitute addiction.
Specialty programs are available for specific populations, including veterans, adolescents, LGBTQ+ individuals, women, and working professionals and executives.
Frequently asked questions
Yes. NIDA, the American Society of Addiction Medicine (ASAM), the American Psychiatric Association, and the World Health Organization all classify addiction as a chronic brain disease. It produces measurable changes in brain structure and function, it has identifiable genetic and environmental risk factors, and it responds to medical treatment. Describing addiction as a moral failure is inconsistent with the clinical evidence and is one of the factors that prevents people from seeking care.²
Physical dependence occurs when the body adapts to a substance such that reducing or stopping use causes withdrawal symptoms. A person can be physically dependent on a medication a doctor prescribed without having a substance use disorder. Addiction (moderate-to-severe SUD) adds the component of compulsive use and continued use despite clear harm. Both conditions can coexist, but dependence alone does not equal addiction.³
Genetics play a significant role: NIDA estimates they account for 40–60% of individual risk.⁵ Having a family history of addiction raises statistical vulnerability without making a substance use disorder inevitable. Environmental factors, developmental timing, and mental health all interact with that genetic risk, and protective factors can reduce it meaningfully.
Yes. Millions of people in the United States are in sustained recovery from addiction. Recovery looks different from person to person — some reach it through inpatient treatment, others through outpatient therapy and medication, others through peer support. Relapse is common and does not mean treatment has failed; it is a recognized feature of a chronic condition, in the same way that a recurrence of symptoms in other chronic diseases is not considered a treatment failure. Long-term outcomes improve substantially with access to ongoing care.¹⁰
There is no fixed timeline. Some people develop a SUD after a relatively brief period of heavy use, particularly with substances that carry high addiction potential such as opioids or methamphetamine. Others use for years without meeting the clinical criteria for a disorder. Individual biology, genetics, mental health, and the substance itself all affect how quickly disordered patterns develop. Early, frequent, or heavy use accelerates risk across all substance categories.⁵
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References
- Substance Abuse and Mental Health Services Administration. 2023 National Survey on Drug Use and Health (NSDUH): Results. Rockville, MD: SAMHSA; 2024.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Washington, DC: American Psychiatric Publishing; 2013.
- National Institute on Drug Abuse. Understanding drug use and addiction DrugFacts. Published January 2023. https://nida.nih.gov/publications/drugfacts/understanding-drug-use-addiction. Accessed March 2026.
- Cleveland Clinic. Substance use disorder (SUD). Updated November 2025. https://my.clevelandclinic.org/health/diseases/16652-drug-addiction-substance-use-disorder-sud. Accessed March 2026.
- National Institute on Drug Abuse. Drugs, brains, and behavior: The science of addiction. Updated April 2020. https://nida.nih.gov/publications/drugs-brains-behavior-science-addiction. Accessed March 2026.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Washington, DC: American Psychiatric Publishing; 2013:490–491.
- Centers for Disease Control and Prevention. About adverse childhood experiences. Updated 2024. https://www.cdc.gov/aces/about/index.html. Accessed March 2026.
- Centers for Disease Control and Prevention. Drug overdose deaths. Updated 2025. https://www.cdc.gov/drugoverdose/deaths/index.html. Accessed March 2026.
- Substance Abuse and Mental Health Services Administration. Co-occurring disorders and other health conditions. Updated 2023. https://www.samhsa.gov/co-occurring-disorders. Accessed March 2026.
- McLellan AT, Lewis DC, O’Brien CP, Kleber HD. Drug dependence, a chronic medical illness: implications for treatment, insurance, and outcomes evaluation. JAMA. 2000;284(13):1689–1695. doi:10.1001/jama.284.13.1689
