It’s usually a choice the first time someone uses drugs or alcohol. But, repeated use can cause changes in the brain that drive a person to use over and over again. Eventually, their drug use has damaging consequences, but they continue to abuse drugs or alcohol. This is an addiction, a disease that affects thinking, behavior, and relationships.

The Definition Of Addiction

Addiction is defined as a complex brain disease with social, environmental, and biological influences. All things capable of stimulating a person can become addictive, and once a habit becomes an obligation, it’s usually considered an addiction. Once addicted, a person may need the substance or activity to avoid unpleasant feelings of withdrawal.


Drug and alcohol addictions are called Substance Use Disorders (SUDs)

Drug and alcohol addictions are also called substance use disorders (SUDs). This is the medical and scientific term for drug addiction and is characterized by:


  • compulsive use
  • continual use despite harmful consequences
  • impaired judgment
  • intense cravings
  • lack of control relating to substance use
  • risky use
  • social problems (relationships, work, or school)

Addiction Vs. Dependence And Tolerance

There are many terms used to describe addiction. The words addiction, dependence, and tolerance are sometimes used interchangeably but are in fact different. Each word describes an effect on the brain and body, and it’s important to know the difference.


  • Tolerance – tolerance occurs when a person no longer responds to drugs or alcohol like they first did. This means they’ll have to use more and more to feel the effects.
  • Dependence – dependence means a person will experience uncomfortable symptoms of withdrawal when they stop use. Withdrawal causes physical and psychological symptoms that can be mild or life-threatening, depending on the drug of abuse.
  • Addiction – addiction, unlike tolerance or dependence, is a disease. This means a person has a disorder with specific signs and symptoms that erode on daily functioning, relationships, and health.

A person can develop a dependence or tolerance to drugs or alcohol without being addicted. However, because of how drugs affect the brain, addiction will likely follow.

Drug Addiction And The Brain

The brain is made up of many different parts that work together and communicate with each other. This essential organ allows people to think, breathe, move, speak, and feel. Once drugs enter the brain, they mess up the normal processes.

A chemical in the brain called dopamine is naturally released when a person experiences a reward or pleasure, like eating or listening to music. Drugs trick the brain by stimulating the “reward circuit” and producing unnatural levels of dopamine, the feel-good chemical. This overflow of dopamine causes the person to feel euphoria or intense happiness.

After a period of repeated use, the brain gets used to the extra dopamine. The brain produces less dopamine naturally, and the person begins to feel little to no pleasure when not using drugs. Long-term use can cause other chemical changes in the brain that may affect:


  • behavior
  • decision-making
  • judgment
  • learning
  • memory
  • stress

Addiction Risk Factors

Although it’s mostly understood what goes on in the brain when a person is addicted to drugs, it’s impossible to know how many times it takes to use a drug before becoming addicted. However, risk factors, like genes, environment, and development, can increase the chances that a person develops an addiction:


  • Early use – the earlier a person begins to use drugs, they more likely they are to become addicted. Early use can occur as a result of genes, unstable family relationships, mental illness, physical or sexual abuse, and other social or biological factors.
  • Home and family – the risk of developing an addiction is increased when young people grow up around parents, older siblings, or other family members who abuse drugs or alcohol or engage in criminal activities. Also, genetics may come into play if the family has a history of substance abuse.
  • Method of use – the way a person takes a drug can increase addiction risks. Smoking or injecting drugs enter the brain almost instantly and produce powerful and intense highs. But, these methods wear off quickly, making the person crave more. Many researchers believe this leads to repeated use and eventual addiction.
  • Peers and school – friends and acquaintances at school, or elsewhere, who abuse drugs can pressure others into trying them for the first time. Addiction risks increase when peer pressure is combined with academic failure and poor social skills.


Addiction genes, addiction environment, and addiction development

Addiction can occur at any time, but the earlier a person uses drugs, the more likely they are to become addicted. Plus, the more risk factors a person is exposed to, the more likely they will develop an addiction when they use drugs.

Warning Signs Of Addiction

Because drug and alcohol use severely affects a person, there are many warning signs of addiction. Some physical signs of addiction include:


  • bloodshot eyes
  • change in appearance or neglecting personal hygiene
  • change in pupil size (larger or smaller)
  • lack of coordination or balance
  • a runny nose
  • sudden weight loss/gain
  • slurred speech

Some behavioral signs of addiction can include:


  • continual drug use despite harm to relationships and self
  • drug tolerance (having to take more and more)
  • drug use is a top priority
  • experiencing withdrawal symptoms when they stop use
  • legal troubles or asking for money
  • neglecting responsibilities at home, work, or school
  • no longer enjoying favorite activities
  • secretive behaviors
  • use more drugs than intended and can’t stop
  • using drugs in dangerous situations

Other warning signs can be psychological, and the person may show increased anxiety and paranoia. They may appear “spaced-out,” seem tired, and lack motivation. Unexplained changes in personality may lead to unusual energy, mood swings, and uncommon outbursts of anger.

Each person responds to drugs differently, and different drugs cause different signs and symptoms. Drug use truly becomes a problem when a person meets the criteria for a substance use disorder (SUD).

The Most Common Substance Use Disorders

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V), which is the manual used by clinicians to diagnose and classify mental disorders, lists criteria for substance use disorders (SUDs). To meet the criteria for an SUD, a person must show symptoms for at least 12-months, including impaired control, social impairment, risky use, and tolerance/dependence/withdrawal.

The most common substance use disorders include:


Commonly abused stimulants include cocaine, amphetamine, and methamphetamine. Opioids include prescription painkillers (Vicodin, OxyContin), fentanyl, and heroin. Other prescription drugs, like Xanax or Valium, are also addictive and may result in a substance use disorder.

Myths About Drug And Alcohol Addiction

Although drug use is initially voluntary, many believe addiction occurs because people lack moral principles or are too lazy to stop use. This is false, and the following includes common myths surrounding addiction.

MYTH: Willpower is all it takes to overcome addiction.

FACT: A person’s brain changes when they use drugs, which makes it hard to stop.


MYTH: You have to hit “rock bottom” before getting help for addiction.

FACT: Treatment can be effective whenever a person recognizes they have a problem and need help.


MYTH: Addiction is a helpless disease and there’s nothing you can do about it.

FACT: Treatment can effectively treat the brain disease of addiction.


MYTH: People must really want to get clean before receiving treatment.

FACT: Addiction specialists are trained to motivate people to get clean and engage in treatment.


MYTH: Relapse means treatment failed.

FACT: While relapse is common, it doesn’t mean treatment isn’t working.

Drug And Alcohol Addiction Treatment Plans 

Addiction is a treatable disease. But, there is no right treatment for everyone, and the best approach is a highly individualized plan that caters to a person’s specific needs. The most effective treatment is thought to be a combination of medication and behavioral therapy.

Many treatment plans include:


  • withdrawal support during detoxification
  • behavioral therapy
  • medications
  • peer support
  • support groups
  • treatment for other mental health conditions
  • follow-up care


Contact us today and find help for treating addiction.



American Psychological Association—Addictions

American Society of Addiction Medicine—Definition of Addiction

Indian Health Service (IHS)—Addiction Myths, Warning Signs of Drug Abuse and Addiction

National Institute on Drug Abuse (NIDA)—The Science of Drug Abuse and Addiction: The Basics, Treatment Approaches for Drug Addiction, Understanding Drug Use and Addiction

NIDA For Teens—Tolerance, Dependence, Addiction: What’s the Difference?

Brain and Addiction

U.S. National Library of Medicine—Behavioral Addiction versus Substance Addiction