Addiction is a chronic brain disease that causes compulsive activity despite health, social and legal consequences. The disease is caused by a variety of factors and lead to long-term negative consequences that can be deadly.

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A person may seem to make a voluntary choice to try a drug or begin a type of behavior, but a variety of genetic and environmental factors influence those decisions. Those factors increase or decrease the likelihood of an individual becoming addicted to that substance or behavior.

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The disease of addiction can occur after ingesting drugs or alcohol or engaging in activities that stimulate the pleasure centers of the brain. It is exemplified by continued compulsive behavior that compromises a person’s health, career and relationships.

The brain of an addict physically changes when he or she continues the behavior driving their addiction, especially when the addiction involves drugs or alcohol. However, any stimulating behavior can cause changes that lead to addiction.

“Most drugs start off being rewarding,” former National Institute on Drug Abuse Director Dr. Glen Hanson told “That gets the person interested in them… As the addiction proceeds, then some of that shifts. It goes from the reward being the attraction to a compulsive behavior. Compulsive behaviors aren’t necessarily rewarding behaviors.”

Addiction, whether in the form of substance use or other behavior, usually begins with a positive experience. However, the high that drugs give a drug user or the thrill that compulsive behavior gives an addict eventually result in negative long-term consequences that outweigh any short-term benefit.


Laura Clarke of Advanced Recovery Systems gives advice to people battling alcohol or drug addiction.

Depressed man looking out of a window

What Are the Different Types of Addiction?

Addiction can be either behavioral or substance related. An intense feeling of emotional need or physical craving characterizes them both. Both types of addiction carry a number of other similarities, but behavioral addiction does not possess the same physical symptoms that accompany drug addiction. Experts disagree on the similarities and differences between the symptoms and consequences of the types of addictions.

The estimated cost of drug abuse in the united states exceeds nearly $190 billion graphic

Drug Addiction

Drugs are addictive substances that change the way the body — the brain in particular — handles communication and processes information. Long-term drug use causes physical changes in the brain that lead to a substance use disorder. Different drugs affect the body differently.

Stimulants, such as tobacco, cocaine or prescription amphetamines, stimulate the brain and nervous system, causing increased alertness. Depressants, such as barbiturates and benzodiazepines, slow activity in the brain and nervous system, causing relaxation. Hallucinogens, such as LSD and PCP, drastically disrupt the way the brain and nervous system communicate, causing hallucinations.

“The kind of treatment you provide is very individualized. It depends on who the person is, what support systems they have in place and their dedication.”

Dr. Glen Hanson, Former Interim Director of NIDA, Director of the Utah Addiction Center

Alcohol Addiction

Alcohol addiction is often referred to as alcoholism or an alcohol use disorder. It’s one of the most common addictions in the United States, with an estimated 16.6 million suffering from the disease. Alcohol addiction occurs when regular, excess drinking causes harm or distress.

Types of problem drinking include:

Alcohol dependency and alcohol abuse
Once categorized as separate disorders, now commonly referred to as an alcohol use disorder.
Binge drinking
Occurs when an individual consumes a high amount of alcohol, between four and five drinks, in a single day.
Heavy drinking
Occurs when an individual consumes five or more drinks on five different occasions in a single month.

Learn more about alcohol addiction

Illicit Drug Addiction

Illicit drugs are outlawed substances consumed by individuals trying to obtain a high, altered perception of reality or feelings of relaxation and happiness. The drugs cause desired short-term disruptions in the brain, but they also cause undesirable long-term changes to the brain and other vital organs in the body, leading to drug addiction.

Common drug addictions include:

  • Marijuana
  • Heroin
  • Cocaine/crack
  • Synthetic drugs such as bath salts and spice

Prescription Drug Addiction

Prescription drugs are approved medications used to treat symptoms of diseases and other medical conditions. Even when used as prescribed, they can cause physical changes that can lead to addiction. When they’re used in any way other than as prescribed by a doctor, the likelihood of prescription drug addiction drastically increases.

Common drugs that cause prescription drug addiction include:

  • Opioids, including oxycodone and hydrocodone.
  • Benzodiazepines, such as Xanax and Valium.
  • Amphetamines, such as Adderall and Ritalin.
  • Sedatives, including Ambien and Lunesta.

Learn more about prescription drug addiction

Behavioral Addiction

As with drugs, certain behaviors cause brief feelings of happiness or euphoria. However, some long-term behaviors cause a person to lose control of their actions. People suffering from these addictions experience symptoms similar to those of drug addicts, including cravings, tolerance, withdrawal and relapse.

Common behavioral addictions include:

  • Gambling
  • Sex
  • Eating
  • Internet
  • Shopping
  • Video Games

Multiple Addictions and Co-Occurring Disorders

Research indicates people who suffer from substance abuse disorders are very likely to suffer from co-occurring mental health disorders and vice versa. An individual can suffer from a behavioral addiction, a drug addiction and a mental health disorder all at the same time.

Common co-occurring mental health disorders include:

man talking to a group about his issues

How Is Addiction Recognized?

Addiction affects people differently. The visible and invisible symptoms of addiction differ depending on the drug or behaviors causing the addiction, but most addictions cause a person to act differently. A person’s appearance may change. They may take more risks, neglect regular activities and begin having problems with personal relationships.


Brett Watson, in recovery from addiction, discusses how he recovered from addiction.

How Is Tolerance Different from Addiction?

Tolerance refers to a physical adaptation within the body in which an individual requires a higher amount of drugs — or a greater amount of behavioral activity — to achieve the same effect. It is a common symptom of addiction, but an increased tolerance does not always mean addiction is present.

How Is Physical Dependency Different from Addiction?

Dependency is a physical adaptation in which the body craves a substance or behavior in order to function normally. Dependency is often accompanied by an increase in tolerance. It is also a common symptom of addiction, but someone can be dependent on a drug without being addicted to it if it does not cause compulsive, harmful behavior.

What Is a Functioning Addict?

High-functioning addicts are people who suffer from a drug or behavioral addiction but are still able to perform at a high capacity in work, social or other settings. However, they are negatively affected by their addiction despite their appearance. They may suffer less obvious consequences of addiction, such as financial or health problems.

DNA strands

What Causes Addiction?

A number of factors contribute to addiction. On the surface, addiction is caused by physical changes in the brain that make the body crave certain substance or behaviors and react negatively when it doesn’t receive it. However, genetic and environmental risk factors contribute to addiction on a deeper level.

Genetic Risk Factors

Addiction runs in families. More than 100 genetic traits that increase someone’s risk for addiction have been discovered. They range from genes that affect the way someone physically responds to a substance to genes that influence compulsive and risky behavior.

Environmental Risk Factors

Environmental risk factors play almost as much of a role in addiction as genetics. Children raised in high-risk environments — for example, homes in which drug use is common or stress is high — are more likely to develop an addiction later in life, as are people exposed to traumatic events.

“Most drugs start off being rewarding. That gets the person interested in them… As the addiction proceeds, then some of that shifts. It goes from the reward being the attraction to a compulsive behavior. Compulsive behaviors aren’t necessarily rewarding behaviors.”

Dr. Glen Hanson, Former Interim Director of NIDA, Director of the Utah Addiction Center
troubled woman looking off into the distance

What Are the Symptoms of Addiction?

Drugs and compulsive behavior can cause both positive and negative consequences in the short term. Addiction begins when negative long-term symptoms begin to develop.

In 2013, 54.1 percent of new illicit drug users were under 18 years of age. Jail cells

Source: National Institute on Drug Abuse


Increased tolerance and dependency are common physical symptoms of addiction. Other physical symptoms include decreased energy and ability to focus. Addiction can also cause problems with blood pressure, heart rate and memory.


People who suffer from addiction often feel withdrawn from life. They lose interest in hobbies and activities they once found enjoyable and disconnect from friends and family. Feelings of sadness, loneliness and desperation are common.


Addicts often participate in high-risk behaviors to support their addiction. Their mental health suffers because addiction worsens existing mental health disorders or causes new ones. Suicide rates are high among addicts.

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What Are Other Complications of Addiction?

Addiction eventually becomes the most important thing in an addict’s life, and maintaining the addiction becomes their top priority.

  • money icon


    Whether it’s buying drugs, gambling or compulsively shopping, addicts almost always run out of money. An inability to earn a reliable income may force them into crime or bankruptcy.

  • calendar icon


    A person suffering from addiction loses track of personal goals and ambitions. Their behavior eventually causes pain and suffering among friends and family.

  • building icon


    People who abuse substances or perform compulsive behavior may be able to function at work or school for a while, but their performance eventually suffers as their addiction progresses.

  • caution icon

    Risky Behavior

    Addicts often exhibit high-risk behavior. They may steal to support their addiction, contract diseases by injecting drugs with shared needles or get into accidents while under the influence of drugs.

group of people talking during a support group

How Is Addiction Treated?

Addiction and co-occurring mental health disorders can be effectively treated at addiction rehabilitation centers and other health care facilities. Personalized treatment plans help ease symptoms of withdrawal, teach individuals to live without their addictions and prepare for the rest of their lives.

  • hospital icon


    Addiction treatment almost always begins with medical detox and medical treatment for co-occurring disorders. It transitions into counseling and behavioral therapy, and often involves 12-step programs or other forms of peer support.

    Learn more about treatment for addiction
  • sober home icon


    Recovery is a lifelong effort for most addicts. It begins with a transition back to normal life via sober houses or transitional living facilities. Former addicts may continue to take medications to ease symptoms of withdrawal and attend support group meetings.

    Learn more about recovery from addiction
  • support ribbon icon


    People recovering from addiction need help. Support groups like Alcoholics Anonymous and Narcotics Anonymous provide free support systems, and the only requirement is for members to make a conscious effort to achieve sobriety.

    Learn more about support systems
  • stop hand icon


    Addiction can be prevented. Genetic and environmental factors may increase someone’s risk for drug abuse, compulsive behavior and addiction, but steps can be taken to decrease that risk. Avoiding high-risk situations, decreasing stress and learning about addiction can prevent it from happening.

How Can Family Members Help?

Families are often the most effective support systems for people suffering from addiction, but they suffer side effects of their loved one’s behavior, too. A number of resources can help addicts and their families recover.


Laura Clarke of Advanced Recovery Systems encourages family members to love and support a loved one with an addiction.

Family Therapy

Family-focused therapy helps addicts understand underlying causes of their behavior, and it helps family members understand their roles in preventing addiction. Family therapy is generally effective with teens and families with a history of addiction.


Al-Anon is a free support group for people affected by a family member’s alcohol addiction. There are numerous Al-Anon meetings in communities across the country, and Alateen meetings focus on helping teens affected by alcoholism in the family.


The best way to help a person struggling with addiction might be to confront them. When family and friends hold an intervention, they’re reaching out to their loved one in hopes of convincing them to get help.

Medical Disclaimer: aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

Chris Elkins, MA
Senior Content Writer,
Chris Elkins worked as a journalist for three years and was published by multiple newspapers and online publications. Since 2015, he’s written about health-related topics, interviewed addiction experts and authored stories of recovery. Chris has a master’s degree in strategic communication and a graduate certificate in health communication.

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