Illicit Drug Use And Addiction

Medically Reviewed by Johnelle Smith, M.D. on March 17, 2023

Illicit drug use can encompass a wide variety of drug types. Whether a person is using heroin or cocaine, sedatives or stimulants, illicit drug abuse can take a toll on physical, mental, and emotional health.

Illicit Drug Addiction

The prevalence of illicit drug use in the United States is growing and negatively affects the physical and mental health of people who use illicit drugs and their family members or friends.

The addictive nature of illicit drugs causes the people who use them to make poor financial and relational decisions as chemical dependence on the drug often results in a substance use disorder.

Illicit drug addiction also impacts public health through the growing number of overdose deaths.

What Are Illicit Drugs?

Illicit drugs include two groups: drugs that are schedule I controlled substances, such as heroin or LSD, and legal medications that are being sold and used illicitly, such as prescription opioid painkillers.

The four main types of illicit drugs are stimulants, depressants, narcotics, and hallucinogens.

Illicit Drug Abuse In The U.S. Statistics

Illicit drug abuse is a growing problem in the United States.

According to the Substance Abuse and Mental Health Services Administration (SAMHSA), over 20% of people 12 years or older used illicit drugs in 2020.

In that same year, according to the Centers for Disease Control and Prevention (CDC), the number of drug overdose deaths nearly reached 100,000.

Since 1999, the growing prevalence of opioid addiction has caused the percentage of overdose deaths to increase almost the same in both rural and urban areas.

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Types Of Illicit Drugs

There are many different types of illicit drugs that are highly addictive and can cause a variety of health problems, including central nervous system damage and mental illness.


Cocaine is a drug that is synthesized from the coca plant native to South American and Latin American countries.

It is usually sold as a white powder that can be snorted or smoked. It can also be dissolved and injected using a syringe and needle.

People who use cocaine experience intense euphoria and a rush of energy. Cocaine abuse can quickly lead to addiction.

Crack Cocaine

Crack cocaine is a solidified form of cocaine that resembles a white, crystalline rock. It is usually smoked in a glass pipe and produces a short-lived, intense high.

Learn more about crack cocaine abuse.


Methamphetamine (meth) is a powerful stimulant drug that is highly addictive and has very limited medical use.

Meth can be sold as a white powder or as a rock-like form called crystal meth. Methamphetamine addiction may lead to an array of serious health problems, including skin lesions and anxiety.


Heroin is an opiate drug that is derived from the opium poppy plant. People who use heroin may snort it in powder form, smoke it, or intravenously inject it.

Read more about heroin abuse.


Hallucinogens are a category of psychoactive drugs that distort how the brain perceives reality. Common hallucinogenic drugs include LSD, MDMA (ecstasy), and psilocybin mushrooms.

Learn more about hallucinogenic drug abuse.


Ecstasy is popularly known as a party drug predominantly taken by young adults and adolescents.

As a psychoactive and stimulant drug, it is one of several synthetic substances that increase energy and a sense of well-being.

Side effects of ecstasy abuse may include a dangerous increase in body temperature, confusion, or memory problems.


Ketamine is a hallucinogen called a dissociative drug. Unlike ecstasy, ketamine has medical uses as an anesthetic.

When used illicitly, ketamine can be injected, snorted, or smoked. Long-term effects of ketamine include cognitive decline, psychosis, and the development of mental health issues.

Learn more about the risks of ketamine addiction.


LSD is a psychoactive drug that gained popularity in the mid to late 1960s. This hallucinogen has the chemical name lysergic acid diethylamide and is known on the street as “acid.”

While LSD is not known to be addictive, people who engage in LSD abuse can develop a psychological dependence on the substance.

MDMA (Ecstasy/Molly)

MDMA stands for methylenedioxymethamphetamine, also known on the street as molly and ecstasy. It has gained notoriety as a popular substance to use at raves and music festivals.

Symptoms of molly abuse include intense mood swings, paranoia, sleep disturbances, and psychosis.

Magic Mushrooms (Psilocybin)

Psilocybin mushrooms are a hallucinogenic substance that is ingested by eating the mushroom caps or infusing them in teas.

Often referred to as magic mushrooms or shrooms, psilocybin use can produce a powerful psychedelic experience that includes hallucinations and changes in perception.


The term “inhalants” refers to both a type of drug and the method of use.

Household products that contain solvents and aerosols are referred to as inhalants when they’re used illicitly by breathing in the fumes. Inhalant abuse can quickly lead to addiction.

Learn more about inhalant drug use.


DMT refers to a naturally occurring hallucinogenic compound that can be found in ayahuasca, a plant native to South America.

Similar to other psychoactive drugs, DMT has been used to treat mental health disorders such as post-traumatic stress disorder, but it has not been legitimized for medical use.

Learn more about DMT abuse.


Marijuana refers to the dried leaves, flowers, and stems from cannabis plants. It is an illicit substance that is now legal in some states.

Despite the inroads that marijuana has made toward being socially acceptable, its addictive qualities of euphoria and relaxation can lead to physical and behavioral health problems.

Learn more about the dangers of marijuana use.

Illegal Synthetic Drugs

Illegal synthetic drugs are substances that are manufactured in clandestine labs, typically in Mexico or China, and trafficked illegally into the United States.

One of the most common and dangerous of these substances is the synthetic opioid fentanyl, which can easily be mixed into other drugs and cause a fatal overdose.

Learn more about the risks of fentanyl addiction.

Methods Of Illicit Drug Abuse

There are many routes of administering illicit drugs. Some of these methods of abuse may require various types of drug paraphernalia.

Routes of administration include the following:

  • Snorting drugs is typically associated with powdered cocaine, meth, and other medications in pill form that can be crushed and snorted through the nose.
  • Smoking drugs is accomplished by heating the substance in a pipe, cigarette, or piece of aluminum foil to the point you can inhale the fumes.
  • Injecting drugs involves dissolving the substance in water and injecting it intravenously to achieve a near-immediate high.
  • Plugging drugs involves injecting a liquid form of the drug into your anus using a plunger and syringe, suppository, or tampon.

Effects Of Illicit Drugs

Illicit drugs can create many harmful physical and mental side effects on the person using the substance.

Mental Effects Of Illicit Drug Use

Adverse mental health effects are often associated with long-term illicit drug abuse.

While the specific effects will vary depending on the drug, the effects listed below are common among many illicit drugs.

Some of the mental health effects of abusing illicit substances include:

  • confusion
  • depression
  • anxiety
  • paranoia
  • memory problems
  • irritability
  • anger

Physical Effects Of Illicit Drug Use

Illicit drugs can also have damaging physical effects that can seriously impact your health and may even lead to overdose or death.

Physical effects of abusing illicit drugs may include:

  • increased heart rate
  • tremors
  • increased blood pressure
  • chronic cough
  • kidney damage
  • increased risk for cancer
  • liver damage
  • high risk for hepatitis
  • high risk for HIV/AIDS

Signs Of Illicit Drug Abuse

If you suspect that a loved one may be abusing illicit drugs, there are telltale signs to look for that point to substance abuse.

Behavioral Signs Of Illicit Drug Use

People who abuse illicit drugs will typically demonstrate changes in behavior.

These changes may include:

  • secretive behavior
  • evasiveness
  • sudden social changes
  • not showing up for work
  • poor performance in school
  • strain on relationships

Mental And Emotional Signs Of Illicit Drug Use

Illicit drug use can also affect a person’s mental and emotional health. If you suspect that a friend, family member, or loved one is abusing an illicit drug, the signs below may point to substance use.

Mental and emotional signs of illicit drug use include:

  • irritability
  • mood swings
  • change in personality or outlook
  • angry outbursts
  • depressive episodes
  • paranoia
  • anxiety

Physical Signs Of Illicit Drug Use

The physical signs of illicit drug abuse may manifest both in the short term and over a period of time.

Physical signs may include:

  • changes in appetite
  • poor physical appearance
  • abnormal sleep patterns
  • signs of injection drug use, such as track marks
  • pupils that are smaller or larger than normal
  • strange odors on a person’s breath or clothes
  • impaired movements or poor coordination

Any of the above physical signs may be an indication that your loved one needs inpatient rehabilitation for drug addiction.

Treatment For Illicit Drug Addiction

The effects of illicit drug addiction, as well as the psychological factors of addiction, can be treated if you seek help from a qualified drug treatment center.

Some drug treatment facilities can facilitate drug and alcohol interventions for family members who want to confront their loved one battling addiction.

Once a person has enrolled in a substance abuse treatment program, they will have access to an array of evidence-based or holistic treatment options to address their addiction.

Inpatient Treatment

The fundamental component of inpatient drug treatment is that you or a loved one lives in the treatment facility for the duration of the rehab program.

Short-term residential treatment is also referred to as clinical stabilization and usually lasts about 30 days often in a hospital-like setting.

Long-term residential treatment can last 60 days or longer, depending on the overall health of the person attending, the severity of their addiction, and other factors.


Medical detoxification is the process of removing toxins from a person’s body who has developed a physical dependence on drugs or alcohol.

Detox can be both medical, involving drugs and intensive monitoring by healthcare staff, or non-medical. It can occur in an inpatient or outpatient setting.

Medication-Assisted Treatment (MAT)

MAT is an addiction treatment program designed to treat severe addictions. It is accomplished by combining medications and various forms of therapy to manage withdrawal symptoms.

Typically, MAT is utilized to treat alcohol use disorder and prescription drug abuse. Some of the common medications used in MAT for opioid abuse are methadone and buprenorphine.

Outpatient Rehab Programs

Outpatient drug rehab programs are used to treat mild to moderate substance use disorders.

Outpatient care allows clients to continue working and living at home while attending weekly counseling and/or MAT.

Dual Diagnosis Treatment For Co-Occurring Disorders

The risks of developing a substance use disorder are higher when a mental illness is present. This is why many rehab programs incorporate dual diagnosis treatment into their regimen.

During co-occurring disorder care, people will be treated for their addiction as well as the underlying mental health issues that are exacerbating substance abuse.

Aftercare Services

Aftercare recovery programs offer ongoing support for people in recovery after they’ve completed inpatient treatment.

Aftercare services may include attending support groups, telehealth therapy, sober living homes or transitional housing, and case management services.

Risk Factors For Abusing Illicit Drugs

There are several factors that may contribute to a person developing an addiction to illicit drugs.

Influencing factors may include:

  • a family history of drug dependence or alcohol abuse
  • mental illness
  • a history of trauma
  • genetic disposition

FAQs About Illicit Drug Abuse

The information below may answer additional questions about illicit drug use and treatment.

The term “illegal drugs” means that the drug is illegal to use or possess. Using an illegal drug puts you at risk of arrest and being put into the criminal justice system by law enforcement.

Not all illicit drugs are illegal, as some may be medically prescribed but sold on the street for illicit use, or otherwise used not as intended.

One of the most commonly abused illicit drugs in North America is cannabis. Since its legalization in many parts of the United States, marijuana use has increased exponentially.

The street cost of drugs can vary greatly depending on the drug you are purchasing and where it’s being purchased.

For example, heroin can cost between $5 to $20 for a small baggie, while MDMA can cost as much as $25 for one “point” or dose.

There are many street names for illicit drugs that get adopted by dealers and buyers so they can discuss the drug in question without arousing suspicion.

For example, heroin goes under the names smack or China white. Cocaine is often called snow or dust, and PCP is referred to as angel dust.

The detection time for drugs in the system depends largely on the drug, how much has been taken, and the duration of use.

Drugs can be detected in your system in the initial days after the last use through a urine or blood test. While hair follicle tests can detect drugs in your system for months after they’ve been used.

Illicit drugs are classified according to the Controlled Substance Drug Schedules and classifications set up by the U.S. Drug Enforcement Administration (DEA).

There are five schedules that are arranged according to how addictive a substance is and whether or not it has medical use. Schedule I substances represent the most harmful drugs.

Speedballing is the practice of mixing heroin and cocaine and injecting a liquid form into the bloodstream.

People engage in speedballing due to the intense high produced by combining these two substances together.

Find Treatment For Substance Use Disorders Today

You do not have to battle illicit drug abuse alone. Addiction treatment facilities around the United States can assist you or your loved ones on your journey to sobriety.

Call our helpline today for more information. Our team can assist you in finding a treatment provider that works for you.

This page does not provide medical advice. See more

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Medically Reviewed by
Johnelle Smith, M.D. on March 17, 2023
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