Substance use disorder (SUD) is a psychological condition involving changes in thinking and behavior caused by the inability to control the use of substances such as alcohol, tobacco, marijuana, opioids, and other drugs. People with this condition find it especially difficult to stop using substances even when they know the substances are negatively affecting their life.

SUD often leads to neurological changes that affect judgment, decision-making, memory, learning ability, and self-control. Symptoms can include strong cravings, mood swings, unusual movements, and difficulty completing daily tasks.

The good news is that SUD is treatable. Treatment options vary by individual and may include rehabilitation, detoxification, outpatient programs, medication-assisted therapy, and peer support programs such as 12-step groups.

Types Of Substance Use Disorders

SUD can involve both legal and illegal substances. Common types include:

  • Alcohol: Widely used socially but dangerous when overused; heavy drinkers risk severe withdrawal if they suddenly stop.

  • Marijuana Or Cannabis: Can be medicinal or recreational; excessive use may cause dependency and impair cognition.

  • Hallucinogens Or Psychedelics: Includes LSD and PCP; alter perception of reality and can affect behavior.

  • Opioids: Painkillers like oxycodone or codeine may lead to addiction and severe withdrawal symptoms.

  • Heroin: A highly addictive opioid with severe withdrawal risks.

  • Tranquilizers: Includes sedatives, hypnotics, and anxiolytics; often prescribed for anxiety or insomnia but addictive when misused.

  • Stimulants: Drugs like cocaine or methamphetamine temporarily increase energy and focus but carry severe health risks.

  • Nicotine: Found in tobacco and vapes; highly addictive and linked to respiratory disease, heart problems, and cancer.

Symptoms

Recognizing the symptoms of SUD is essential for early intervention. Common signs include:

Dependence On Substances

  • Strong cravings or daily need to use

  • Unsuccessful attempts to cut down or quit

  • Tolerance, requiring higher doses for the same effect

  • Withdrawal symptoms such as shaking, chills, nausea, or diarrhea

Behavioral And Emotional Changes

  • Confusion, disorientation, or brain fog

  • Sudden aggression or violent outbursts

  • Defensiveness when asked about substance use

  • Acting secretively to hide usage

Life Impact

  • Declining work or school performance

  • Skipping meals or neglecting health

  • Spending money on substances despite financial stress

  • Loss of interest in once enjoyable activities

Causes

The exact causes of SUD are complex and involve multiple factors, such as genetics, stress, peer pressure, and prolonged exposure to substances.

People with underlying mental health conditions like depression, anxiety, ADHD, or PTSD have a higher risk of developing SUD. Childhood trauma, neglect, or lack of social support also increase vulnerability.

Among young adults, alcohol, cannabis, and tobacco are the most commonly used substances. Youth are particularly at risk due to peer influence, family history, and mental health struggles.

Diagnosis

If substance use is a concern, a healthcare provider can begin with screenings and laboratory tests.

Diagnostic methods include:

  • Blood or urine tests: Detect recent use of substances.

  • Breathalyzer: Measures alcohol levels.

  • Psychological evaluation: A psychiatrist, psychologist, or counselor will assess mental and behavioral patterns to confirm diagnosis.

Diagnosis requires more than lab tests — a full psychological assessment and collaboration with healthcare providers is necessary.

Treatment

Treatment for SUD is individualized and may involve one or several approaches:

Detox
Medical detox helps patients stop using substances safely while managing withdrawal symptoms under medical supervision.

Inpatient Rehabilitation
Structured, live-in programs offering 24/7 care over weeks or months to stabilize and treat SUD.

Outpatient Programs
Provide therapy and support sessions while allowing patients to continue daily routines. Sessions may be flexible, including evenings or weekends.

Psychotherapy
Talk therapy helps reframe thoughts about substance use, reduce cravings, and develop healthier coping mechanisms.

How To Prevent Substance Use Disorder

Prevention involves personal responsibility, family support, and community programs.

Examples of prevention strategies include:

  • Parent-child communication programs teaching how to talk about alcohol and drugs.

  • STOP Underage Drinking initiatives to reduce early alcohol use.

  • Awareness campaigns such as National Prevention Week that encourage education and community involvement.

Starting prevention early, offering emotional support, and encouraging open conversations can significantly lower risks.

Related Conditions

People with SUD may also face additional risks, including:

  • Gambling addiction or other behavioral addictions

  • Unsafe sexual practices

  • Sharing needles, increasing risk of infection

  • Neglecting health or medical conditions

  • Co-existing mental health disorders such as anxiety, depression, ADHD, or schizophrenia

Living With Substance Use Disorder

Managing SUD can be physically and emotionally challenging. Relapse is common but does not mean failure — it is part of the recovery process for many people.

Continued support from healthcare providers, therapy, and family or peer groups can make recovery more sustainable. Building a strong support network is essential for long-term success.