The Most Common Addictive Drugs

Substance abuse in the United States is one of the leading health conditions impacting millions of lives. Statistically, 165 million people or 60.2% of Americans ages 12 and older currently abuse drugs, including alcohol and tobacco. Since 2000, there have been 700,000 overdose deaths in the U.S., with annual rate increases of 4%.

In comparison to other chronic diseases, the costs associated with drug abuse are as considerable as diabetes and cancer. Costs of substance abuse includes healthcare expenses, lost earnings and income, cost of drug-related crimes, overdoses, and more. 

This article further discusses addiction, addictive drugs, signs of addiction, and treatment options. 

Treatment for Addiction - Illustration by Ellen Lindner

Verywell / Ellen Lindner

What Is Addiction?

According to the American Psychiatric Association, substance use disorder (SUD) is a condition in which there is uncontrolled use of a substance with a detrimental outcome. Individuals with SUD experience changes to the brain’s structure and function that cause cravings, personality and behavioral changes, and more. 

The brain is made up of circuitry and networks of neurons; when a neuron receives signals from other connected neurons, it fires up and sends its own signal to other neurons within the circuit. Working together, different circuits in the brain are responsible for specific functions. 

When drugs are introduced, the neurons sending and receiving signals through their neurotransmitters are disrupted. Because of their chemical composition, certain drugs, like marijuana and heroin, activate neurons that copy natural neurotransmitter functions, allowing the drug to attach itself and activate the neuron, leading to abnormal messaging sent through the brain’s circuits and network.

The basal ganglia, which is responsible for motor control, executive functions (eating and sex) behaviors (habits and routines), and emotions. It’s also known as the brain’s reward circuit so when drugs overstimulate the circuit, it produces euphoria. Yet with repeated use of the drug, the circuit adjusts to the drug’s effect, reducing sensitivity and making it hard to receive other forms of pleasurable stimulation.

Types of Addictive Drugs

When drugs are introduced to the system, dopamine, a neurotransmitter that responds to pleasurable activities is switched on and lights up that network. Below is a list of drugs, including alcohol and tobacco, and how each one affects the brain and contributes to SUD.


Alcohol interferes in the areas controlling balance, memory, speech, and judgment. Long-term, heavy drinking results in changes in the neurons, like size reduction. Alcohol misuse may cause alcohol-induced blackouts, resulting in memory gaps that temporarily block the transfer of memories from short-term to long-term storage. 

Continuing to drink despite clear signs of significant impairments can result in an alcohol overdose. Symptoms include:

  • Confusion
  • Difficulty remaining conscious
  • Vomiting
  • Seizure
  • Trouble breathing
  • Slow heart rate
  • Clammy skin
  • Dulled responses like no gag reflex (which prevents choking)
  • Extremely low body temperature
  • Permanent brain damage
  • Death


Heroin is processed from morphine, which is taken from seed pods of certain poppy plants. It can be snorted through the nose, smoked, or injected. When taken, heroin binds to specific receptors called mu-opioid receptors (MORs) that activate dopamine, resulting in a “rush.” Heroin use is accompanied by:

  • A warm flushing of the skin
  • Dry mouth
  • A heavy feeling in the extremities
  • Nausea, vomiting, and severe itching
  • Drowsiness for several hours
  • Mental function is clouded
  • Slowed heart function and breathing that may be life-threatening or may lead to coma and permanent brain damage


Cocaine is sourced from the coca leaves found in South America. Its purified form is the chemical cocaine hydrochloride. Users can administer cocaine through the nose, intravenously (injecting in a vein), or inhaling. When cocaine is absorbed into the bloodstream, the brain’s reward pathway is stimulated with the release of dopamine, resulting in euphoria or a “high” when taking the drug. Long-term use of cocaine alters how the brain's pathways respond to stress.

Short-term physiological effects of cocaine use include:

  • Constricted blood vessels
  • Dilated pupils
  • Increased body temperature, heart rate, and blood pressure
  • Bizarre, erratic, and violent behavior
  • Restlessness, irritability, anxiety, panic, and paranoia
  • Tremors, vertigo, and muscle twitches

Long-term physiological effects of cocaine use include:

  • Loss of smell
  • Nosebleeds
  • Swallowing problems
  • Irritation of the nasal septum leading to a chronically inflamed, runny nose
  • Damage to body’s organs that can lead to increased risk of stroke and other neurological problems


Methamphetamine or “meth” is an addictive stimulant that affects the central nervous system. It can be ingested orally in pill form, via smoking, snorting, and injecting the powder with either water or alcohol. When it's entered into the bloodstream and reaches the brain, meth increases the amount of dopamine released in the brain, reinforcing the need for more use of the drug.

Short and long-term physical effects of meth use include:

  • Increased wakefulness and physical activity
  • Decreased appetite
  • Faster breathing rate
  • Rapid and/or irregular heartbeat
  • Increased blood pressure and body temperature 
  • Extreme weight loss
  • Severe dental problems known as meth mouth
  • Intense itching, leading to skin sores 
  • Anxiety
  • Changes in brain structure and function
  • Confusion
  • Memory loss
  • Sleeping problems
  • Violent behavior
  • Paranoia
  • Hallucinations


Individuals who smoke habitually are addicted to nicotine. Like other drugs, nicotine affects the brain with the release of dopamine, reinforcing the behavior and leading to addiction. 

Smoking increases the risk of many cancers including lung, mouth, pharynx, larynx, esophagus, stomach, pancreas, cervix, kidney, and bladder. It may also increase the risk of developing acute myeloid leukemia. In addition, it contributes to a number of respiratory diseases including bronchitis, emphysema, asthma, and chronic obstructive pulmonary disease. Smoking also detrimentally affects the cardiovascular system.


Prescription painkillers are similar to heroin in that it can result in euphoria. Opioids are the most common misused painkillers. Opioids affect the areas of the brain that control emotion and reduce the effects of pain. The primary danger of using opioids is an overdose, caused by compounds that interact with the brain stem that controls breathing.

Prescription opioids include:

Side effects of taking opioids include drowsiness, confusion, nausea, constipation, and respiratory depression (slow and ineffective breathing).

Mood Regulation Drugs

Mood regulation drugs are psychiatric drugs that are used to treat bipolar disorder, mania and hypomania, depression (recurrent and severe), and schizoaffective disorder. The three main drugs used include lithium, anticonvulsants, and antipsychotics. Side effects depend on the medication prescribed. Regular monitoring of the drug's strength is needed to keep an eye on potential distress caused by the drug. 


Made from the hemp plant Cannabis sativa, the primary chemical that alters the brain is delta-9-tetrahydrocannabinol, or THC. When marijuana is smoked, THC and other chemicals pass from the lungs into the bloodstream and travel to the brain, resulting in a sense of relaxation. Adverse side effects may include anxiety, fear, and panic. Large doses of marijuana may cause temporary acute psychosis (hallucinations, delusions, and loss of personal identity). 


Stimulants increase attention, energy, blood pressure, heart rate, and breathing rate. Typically they are prescribed to to treat attention-deficit hyperactivity disorder (ADHD). They affect the brain’s monoamine neurotransmitter systems, which include norepinephrine and dopamine. Stimulants intensify the effects of these chemicals.

Like other addictive drugs, they can bring on euphoric feelings. Stimulants also increase blood pressure and heart rate, constrict blood vessels, increase blood glucose, and open up breathing passages. Misuse of these drugs can lead to hostility, paranoia, and psychosis. Taking high doses may lead to possible cardiovascular failure or seizures.


Inhalants include solvents and aerosols, and are found in common household items like spray paints, markers, glues, cleansers, and nitrate prescriptions. Inhalants can be breathed through the nose or mouth in a variety of ways from sniffing fumes to huffing a soaked rag stuffed in the mouth. Inhalants are quickly absorbed into the bloodstream and reach the brain quickly, resulting in an intoxicated state similar to consuming alcohol.

Side effects include: 

  • Slurred speech
  • Inability to coordinate movements
  • Euphoria
  • Dizziness
  • Lightheadedness, hallucinations, and delusions


CNS (central nervous system) depressants include tranquilizers, sedatives, and hypnotics that slow brain activity. These types of drugs help treat sleep disorders and anxiety. The most common prescribed medications include:

  • Benzodiazepines for short-term sleep disorders
  • Non-benzodiazepine sleep medications (have less side effects and less risk of dependence)
  • Barbiturates (used less for anxiety or for sleep disorders due to their higher risk of overdose)

Signs of Addiction

Adverse signs of addiction can be seen in behavior and in symptoms. If you believe a loved one has a substance use disorder, keep an eye out for the following signs and symptoms:

  • Uses substances to the point of intoxication
  • Unusual mood changes
  • Steals money from friends, family, and work
  • Misses work or school
  • Damaged relationships
  • Secretive, defensive behavior
  • Changes in eating and sleeping habits

Physical signs include:

  • Rapid weight changes (gain or loss)
  • Staggered walk
  • Unexplained bruises or marks
  • Needle marks on arms
  • Unexplained breakout of acne/rash
  • Unusual body odor
  • Depressed or anxious
  • Deterioration of personal appearance or hygiene


According to the National Institute on Drug Abuse, addiction is treatable, but it’s not a simple process. Addiction is a chronic disease that can’t be stopped within days, and individuals will need long-term treatment. However, not every treatment is successful with everyone. Treatment will need to address the underlying issues that led to the addiction and not solely on the substance use disorder.

Treatments include:

  • Behavioral counseling
  • Medication
  • Medical devices and applications used to treat withdrawal symptoms or deliver skills training
  • Evaluation and treatment for mental health issues such as depression and anxiety
  • Long-term follow-up to prevent relapse

Follow up may include community support programs like Narcotics Anonymous, Alcoholics Anonymous, and family-based recovery systems.

When to Talk to Your Healthcare Provider

Recognizing that you have a substance use disorder is the first step. Once you’ve acknowledged that you can’t live without the drug or alcohol, seek help as soon as possible. Your healthcare provider will be able to refer you to a drug counselor and any other counseling services that deal with substance use disorder.

A Word From Verywell

Substance use disorder is chronic disease that has adverse effects on individuals, their family, and friends. If you have loved ones with a substance use disorder, don’t ignore it. Get them help immediately. There are many programs available that will be able to help. But remember, treatment is a long process that will require a long-term commitment.

Frequently Asked Questions

  • What makes drugs addictive?

    The brain has a reward pathway that releases dopamine, causing pleasure and euphoria. When we have a positive experience whether it's eating a delicious meal or having sex, dopamine is released. When drugs are ingested in one form or another, it stimulates the reward pathway, releasing dopamine.

  • What are the most addictive drugs?

    Not all drugs are created equal in terms of addiction, but the most addictive drugs include heroin, alcohol, cocaine, barbituates, and nicotine.

  • What other types of addiction are there?

    Other addictions include: gambling, sex, video games, internet, shopping, and food addiction.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Rebeca Schiller
Rebeca Schiller is a health and wellness writer with over a decade of experience covering topics including digestive health, pain management, and holistic nutrition.