Addiction: Definition, Types, Causes and Treatment

Addiction is a chronic, relapsing disorder defined by compulsive substance seeking and use, or compulsive engagement in a behavior, that continues despite harmful consequences. The National Institute on Drug Abuse (NIDA) classifies addiction as a brain disorder because it produces functional changes in the brain circuits that govern reward, stress, and self-control. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnoses the substance form of addiction as substance use disorder (SUD), measured against 11 criteria and graded mild, moderate, or severe.

According to the Substance Abuse and Mental Health Services Administration's (SAMHSA) 2024 National Survey on Drug Use and Health (NSDUH), 48.4 million Americans aged 12 or older — 16.8 percent of the population — had a substance use disorder in the past year. Alcohol use disorder affected 27.9 million people, drug use disorder affected 28.2 million people, and opioid use disorder affected 4.8 million people.

U.S. overdose deaths are falling. The United States recorded 79,384 drug overdose deaths in 2024, and the age-adjusted overdose death rate fell 26.2 percent from 2023 — the largest one-year drop of the 2014-2024 period, according to the CDC's National Center for Health Statistics. New Jersey recorded more than 2,800 overdose deaths in 2023, an 11 percent decline from 2022, and preliminary 2024 data shows a further decrease, according to the New Jersey Department of Health.

Addiction is treatable, and treatment remains underused: among Americans classified as needing substance use treatment in 2024, 19.3 percent — 10.2 million people — received it, per the 2024 NSDUH. Valley Spring Recovery Center, a New Jersey-licensed treatment center in Norwood, Bergen County, treats substance use disorders at three levels of care: Partial Care, Intensive Outpatient, and Outpatient.

What Is Addiction?

Addiction is a chronic, relapsing disorder characterized by compulsive drug seeking and use despite adverse consequences, as the National Institute on Drug Abuse defines it in "Drugs, Brains, and Behavior: The Science of Addiction." NIDA considers addiction a brain disorder because it involves functional changes to brain circuits involved in reward, stress, and self-control.

The DSM-5 folded the older diagnoses of substance abuse and substance dependence into the single diagnosis of substance use disorder. A person meets the diagnosis by satisfying 2 or more of 11 criteria within a 12-month period, according to Jahan, Azmi R. and Burgess, Doug M.'s 2023 StatPearls review "Substance Use Disorder," published by the National Library of Medicine. Severity scales with the criterion count: 2 to 3 criteria is mild, 4 to 5 is moderate, and 6 or more is severe.

Every substance use disorder shares one mechanism: a reward circuit in the brain retrained to demand the substance.

How Does Addiction Change the Brain?

Addiction changes the brain by flooding the reward circuit with dopamine, then weakening the circuits that regulate stress and self-control, according to NIDA's "Drugs, Brains, and Behavior: The Science of Addiction." Brain imaging in that report shows people with a history of cocaine use disorder carry lower levels of the D2 dopamine receptor in the striatum than people who never used cocaine.

Repeated dopamine surges teach the brain to rank the substance above natural rewards, including food, social connection, and accomplishment. Addiction also alters the brain's self-control circuits, according to NIDA's report "Drug Misuse and Addiction" — which is why willpower alone fails as a treatment plan: the circuitry that governs decisions is itself changed.

The brain changes also separate addiction from the related but distinct state of physical dependence.

What Is the Difference Between Addiction and Dependence?

The difference between addiction and dependence is that addiction is compulsive use despite harmful consequences, while dependence is the body's physical adaptation to a substance, producing tolerance and withdrawal when use stops. A hospital patient on long-term opioid therapy develops dependence without addiction, and the DSM-5 omits the tolerance criterion for medications taken under physician supervision, per Jahan and Burgess's StatPearls review.

Dependence without addiction resolves through a physician-supervised taper. Addiction adds the behavioral engine — craving, loss of control, and continued use despite consequences — and requires treatment of the behavior, not only the physiology. Both patterns appear across every category of addiction.

What Are the Types of Addiction?

The 2 types of addiction are substance addiction, involving alcohol or drugs, and behavioral addiction, involving compulsive engagement in activities such as gambling. The DSM-5 formalized the second category by moving gambling disorder into its substance-related and addictive disorders chapter, according to Rash, Carla J. and Petry, Nancy M.'s 2016 article "Gambling Disorder in the DSM-5," published in Current Addiction Reports.

Substance addiction covers the alcohol and drug use disorders tracked by federal survey data. Alcohol is the most common substance used among people 12 and older in the United States, according to the CDC, and alcohol use disorder affected 27.9 million Americans in 2024. Drug addiction — spanning opioids, stimulants, cannabis, sedatives, and hallucinogens — affected 28.2 million people, or 9.8 percent of Americans 12 or older, up from 8.7 percent in 2021, per the 2024 NSDUH.

The following table compares the 4 largest substance classes by past-year use disorder prevalence and by FDA-approved medication availability, using figures from SAMHSA's 2024 NSDUH annual national report and medication lists published by SAMHSA and NIDA.

Behavioral addiction is compulsive engagement in a rewarding activity rather than use of a psychoactive substance. Gambling disorder holds full DSM-5 diagnostic status, and compulsive patterns around gaming, shopping, sex, exercise, food, and internet use follow the same clinical logic of craving, loss of control, and continued engagement despite harm. The guide to behavioral addictions defines 15 of these patterns, their warning signs, and their treatments.

Across both types, the same risk factors decide who develops addiction and who does not.

What Causes Addiction?

Addiction is caused by the interaction of biological, environmental, and developmental risk factors — no single factor determines whether a person will become addicted to drugs, according to NIDA's report "Drug Misuse and Addiction." NIDA estimates that genes, including the effects environmental factors have on a person's gene expression, account for between 40 and 60 percent of a person's risk of addiction.

NIDA groups addiction risk factors into 3 domains:

• Biology: Genes, including the effects of environment on gene expression, account for 40 to 60 percent of addiction risk, and NIDA lists a person's stage of development among the biological factors that modify that baseline.
• Environment: Family, school, and neighborhood conditions shape exposure and coping. Parents or older family members who use drugs or misuse alcohol increase children's risk of future drug problems, per NIDA, and teens who use drugs sway other adolescents to try drugs for the first time.
• Development: The brain continues to develop into adulthood, and the prefrontal cortex — the region NIDA credits with assessing situations, making sound decisions, and keeping emotions and desires under control — is still forming during adolescence. The earlier people begin to use drugs, the more likely they are to develop serious problems, according to NIDA.

Risk factors predict vulnerability; the DSM-5 criteria identify when substance use has crossed into disorder.

What Are the Signs and Symptoms of Addiction?

The signs and symptoms of addiction are the 11 DSM-5 substance use disorder criteria, which the American Psychiatric Association groups into impaired control, social impairment, risky use, and pharmacological criteria (tolerance and withdrawal). A person meeting 2 or more criteria within 12 months qualifies for the diagnosis, per Jahan and Burgess's 2023 StatPearls review "Substance Use Disorder."

The 11 criteria fall into 4 clusters:

• Impaired control: taking the substance in larger amounts or for longer than intended, repeated unsuccessful attempts to cut down, excessive time spent obtaining or recovering from the substance, and craving.
• Social impairment: failing obligations at work, school, or home; continuing use despite relationship damage; and abandoning occupational, social, or recreational activities.
• Risky use: using the substance in physically hazardous situations, and continuing use despite a physical or psychological problem the substance causes or worsens.
• Pharmacological adaptation: tolerance, in which the same dose produces less effect, and withdrawal, in which stopping produces physical and psychological symptoms.

Criterion count sets severity: 2 to 3 criteria is a mild disorder, 4 to 5 is moderate, and 6 or more is severe. Among the 4.8 million Americans with a past-year opioid use disorder in 2024, 65.4 percent had a mild disorder and 19.3 percent had a severe disorder, per the 2024 NSDUH annual national report. Untreated, those symptoms compound into measurable physical, psychological, and social damage.

What Are the Effects of Addiction?

The effects of addiction are premature death, chronic physical disease, mental health deterioration, and progressive damage to relationships, work, and finances. Overdose is the sharpest effect: the United States recorded 79,384 drug overdose deaths in 2024, according to Garnett, Matthew F. and Miniño, Arialdi M.'s January 2026 report "Drug Overdose Deaths in the United States, 2023-2024," National Center for Health Statistics.

The 2024 total marks a turning point. The age-adjusted overdose death rate fell from 31.3 to 23.1 deaths per 100,000 — a 26.2 percent decline, the largest one-year drop of the 2014-2024 period — and the death rate involving synthetic opioids other than methadone, the category dominated by fentanyl, fell 35.6 percent. The full breakdown by age, sex, race, and drug type appears in the CDC's NCHS Data Brief No. 549.

Alcohol kills on a longer clock. Excessive alcohol use caused about 178,000 U.S. deaths each year during 2020-2021 and shortened the lives of those who died by an average of 24 years, according to the CDC's "Facts About U.S. Deaths from Excessive Alcohol Use." Two-thirds of those deaths — about 117,000 per year — came from chronic conditions, including liver disease, heart disease, and cancer.

New Jersey mirrors the national decline. The state recorded more than 2,800 overdose deaths in 2023 — more than 7 residents per day — an 11 percent decline from 2022, with preliminary 2024 data showing a further decrease, according to the New Jersey Department of Health's August 2025 announcement. The state operated 54 authorized harm reduction centers as of July 31, 2025, with at least one in each of New Jersey's 21 counties.

Mortality statistics understate the damage, because addiction also dismantles the systems a person lives inside: marriages, parenting, friendships, and employment. The guide to addiction effects on relationships documents that erosion across family, social circles, and society. Measuring the damage in a single person starts with formal diagnosis.

How Is Addiction Diagnosed?

Addiction is diagnosed through a clinical interview that scores the 11 DSM-5 substance use disorder criteria, supported by validated screening instruments including the AUDIT (Alcohol Use Disorders Identification Test), the DAST-10 (Drug Abuse Screening Test), and the CAGE questionnaire.

Screening precedes diagnosis. Standardized instruments flag a probable disorder in minutes; the library of drug addiction screening tests explains 15 instruments, their scoring thresholds, and the settings where each applies. A positive screen leads to a diagnostic evaluation with a clinician, and the evaluation feeds placement: the ASAM Criteria — the American Society of Addiction Medicine's placement framework — match a patient's diagnosis severity, withdrawal risk, and recovery environment to a numbered level of care.

Placement matters because addiction treatment is a sequence of matched levels, not a single event.

What Are the Treatments for Addiction?

The treatments for addiction are behavioral therapy, FDA-approved medication, and structured levels of care matched to disorder severity. The combination of medication and counseling successfully treats substance use disorders and improves patient survival rates, according to SAMHSA's guidance "Treatment Options for Substance Use Disorder."

Medication is the evidence anchor for two disorders. The FDA has approved acamprosate, disulfiram, and naltrexone for alcohol use disorder, and buprenorphine, methadone, and naltrexone for opioid use disorder, per SAMHSA. People with opioid use disorder who are treated with methadone or buprenorphine are less likely to die or to have an overdose than those who do not receive treatment, according to NIDA's research report "Medications to Treat Opioid Use Disorder." Uptake stays low: 17.0 percent of Americans with a past-year opioid use disorder received medications for it in 2024, and 2.5 percent of those with alcohol use disorder received medications for that disorder, per the 2024 NSDUH.

Behavioral therapy carries the substance classes that lack an approved medication. Contingency management — a structured incentive program — is the best-studied treatment for methamphetamine use disorder and the one most associated with treatment success, according to NIDA. Cognitive behavioral therapy (CBT), motivational enhancement therapy, and contingency management treat cannabis use disorder, and CBT, dialectical behavior therapy (DBT), motivational interviewing, and family therapy anchor treatment across every substance class.

Outpatient addiction treatment is delivered at ASAM-numbered levels of intensity, stepping down as stability grows. The following table lists the 3 substance use levels of care at Valley Spring Recovery Center in Norwood, New Jersey, with the schedule and duration of each stage. Partial Care is the New Jersey licensure term for what national frameworks call a partial hospitalization program (PHP); it is day treatment, and clients live at home.

Valley Spring Recovery Center operates under New Jersey substance use treatment license #200887, caps its therapist-to-patient ratio at 8:1, and runs process groups under 10 people. On-site medication-assisted treatment uses buprenorphine (Suboxone, Brixadi) and naltrexone (Vivitrol) alongside individual and group therapy. The treatment programs at Valley Spring Recovery Center page details the admission criteria, daily structure, and insurance verification for each level.

Treatment starts recovery; maintaining recovery is its own clinical phase.

How Do People Recover From Addiction?

People recover from addiction at rates comparable to other chronic illnesses, through sustained treatment, relapse management, and long-term support. In 2024, 74.3 percent of the 31.7 million U.S. adults who perceived they ever had a problem with alcohol or drugs — 23.5 million people — considered themselves to be in recovery or to have recovered, according to SAMHSA's 2024 NSDUH.

Relapse rates for substance use disorders run 40 to 60 percent, comparable to relapse rates for hypertension and asthma at 50 to 70 percent, according to NIDA's report "Treatment and Recovery." A return to use signals that treatment needs to resume or adjust, the same way a blood pressure spike signals a medication change — not a moral failure. The guide to recovery from addiction covers the maintenance phase: warning signs of a return to use, relapse prevention planning, and long-term support structures.

Help is available at 3 levels of urgency. Call or text 988, or chat at 988lifeline.org, to reach the 988 Suicide and Crisis Lifeline for any mental health or substance use crisis. Call SAMHSA's National Helpline at 1-800-662-4357 for 24/7 treatment referrals nationwide. Call Valley Spring Recovery Center at (855) 924-5320 to speak with the Norwood, New Jersey admissions team about a clinical assessment and insurance verification.

What Are the Most Common Questions About Addiction?

The 7 questions below cover the definitions, prevalence figures, and treatment facts people search most about addiction. The guides linked throughout this page carry the full detail.

Is Addiction a Disease?

Yes, addiction is a disease. NIDA defines addiction as a chronic, relapsing disorder and considers it a brain disorder, because it involves functional changes to brain circuits involved in reward, stress, and self-control.

What Is the Most Common Addiction in the United States?

Alcohol addiction is the most common addiction in the United States. The CDC names alcohol the most common substance used among people 12 and older, and SAMHSA counted 27.9 million people with a past-year alcohol use disorder in 2024.

Can Addiction Be Cured?

No, addiction is managed rather than cured. NIDA calls addiction a treatable disorder: treatment enables people to counteract addiction's disruptive effects on their brain and behavior, and relapse rates match those of hypertension and asthma.

How Long Does Addiction Treatment Take?

Treatment length scales with the level of care. At Valley Spring Recovery Center, Partial Care runs 4 to 6 weeks, intensive outpatient runs 6 to 8 weeks, and outpatient runs 8 to 12 weeks, then continues as clinically needed.

Does Insurance Cover Addiction Treatment?

Yes, in-network health plans cover addiction treatment at Valley Spring Recovery Center, which holds in-network contracts with major commercial and union insurance payers. The admissions team verifies each patient's specific benefits by phone at (855) 924-5320.

Are Behavioral Addictions Real Diagnoses?

Yes. The DSM-5 moved gambling disorder from the impulse-control chapter into its substance-related and addictive disorders chapter — formal diagnostic recognition of behavioral addiction, per Rash and Petry's 2016 article in Current Addiction Reports.

Where Does Someone Get Help for Addiction in New Jersey Right Now?

Call or text 988, or chat at 988lifeline.org, for immediate crisis support. Call SAMHSA's National Helpline at 1-800-662-4357 for 24/7 referrals. Call Valley Spring Recovery Center in Norwood at (855) 924-5320.