Get help today 888-744-0069 or sign up for 24/7 text support.
American Addiction Centers National Rehabs Directory

Health Effects of Drug Misuse and Addiction

Substance misuse and addiction can have serious short- and long-term effects.1 The physical effects of drugs and alcohol vary according to the type of substance, duration of use, and method of administration.1 Recovering from addiction can be a difficult process, but knowing the health benefits may provide additional motivation for sobriety.

This article will explore the health impact of addiction, the effects of specific drugs and their methods of use on different body systems, and where to begin recovery.

What Do Drugs Do to the Body?

Drugs and alcohol can disrupt certain types of brain signaling and adversely impact many physiological processes.2 The specific type of brain changes that accompany drug and alcohol use vary by substance, accounting for the distinct range of effects for each. In addition to their impact within the brain, some drugs can lead to widespread harm throughout multiple parts of the body. A few examples are examined below.

The Effects of Cocaine on the Body

Almost immediately after taking cocaine, a person will commonly feel euphoric and alert, and might experience increased sensitivity to sight, sound, and touch.3 Cocaine may also cause extreme changes in body temperature, heart rate and rhythm, and digestive upset.3 Depending on the specific method with which it is used, cocaine’s intoxicating high may last 30 minutes at the most. Cocaine use can lead to significant medical complications. Though rare, cocaine has been associated with sudden death with first-time use.3

Long-term effects of cocaine use may include nasal structural damage, gastrointestinal injury, infections from injection use, and psychotic features such as paranoia.4 Many of cocaine’s toxic effects are due to the way cocaine constricts blood vessels and other cardiovascular changes.3

The Effects of Alcohol on the Body

Alcohol has the potential to affect several body systems with either short- or long-term use. Heavy drinking and severe intoxication can lead to death by slowing down the breathing and heart rate, choking due to a dulled gag reflex, or accidents from mental confusion or loss of conciousness.5

Long-term use can increase your risk of multiple cancers, lead to severe liver damage, or damage the heart.6 Weakening of the heart muscle, stroke, high blood pressure, and pancreatitis are all potential results of chronic alcohol misuse.6

The Effects of Heroin on the Body

Heroin’s effects on the body commonly include flushed skin, nausea, and itchiness.7 Heroin binds to opioid receptors throughout the body to influence the body’s ability to feel pain and can dangerously affect heart rate and breathing.7 Death by overdose is often due to an extreme slowing or cessation of breathing.7

Chronic and repeated use of heroin may also lead to collapsed veins, heart or blood infections, chronic constipation, or lung complications.7 Other opioids have similar side effect profiles with misuse.8

Long-Term Health Effects of Drug Misuse

Repeated long-term use of drugs or alcohol can have a variety of negative effects on a person’s health.9 The effects are dependent upon various factors. Which substance or substance combinations are used, how often and how much they are used, and the route or method of use can all influence both short- and long-term effects.1

Using drugs or alcohol long-term can increase the risk of addiction development (substance use disorder).1 Chronic misuse also puts a person at a cumulatively increased risk of overdose.2, 4

When physical dependence develops in association with repeated drug or alcohol use, many people will experience withdrawal symptoms if the person reduces their dose or stops taking it.2, 7 Effects of withdrawal can range from mildly uncomfortable to life-threatening, depending on the substance used.10

Though the precise range of symptoms will vary from one substance to the next, some general examples of various withdrawal symptoms include:10

  • Mood changes.
  • Altered sleeping patterns.
  • Extreme fatigue.
  • Changes in appetite.
  • Increased heart rate.
  • Fever, sweating and other flu-like features.
  • Perceptual changes including hallucination.
  • Tremors.
  • Seizures.

In addition to the physical effects of repeated substance misuse, the development of addiction can have widespread effects on a person’s life and relationships.1 Addiction, or substance use disorder, is a chronic brain disease.1 Like many chronic medical conditions, treatment may not be curative, but the condition can be successfully managed to promote lasting recovery.11

In addition to longer-term risks of addiction, dependence and withdrawal, adverse social and interpersonal consequences, chronic substance use can lead to a number of significant, and in some cases devastating, physical health issues—impacting a variety of organ systems such as the brain, heart and cardiovascular system, liver, kidneys, and lungs.


The brain is central to experiencing the thoughts, feelings, and actions that are unique to human beings.2 It works through billions of neurons, cells that communicate throughout the brain, by sending and receiving signals and building connections between different areas.2 Drugs can interfere with neuronal cell signaling through their impact on our brain’s natural chemical messengers, or neurotransmitters.2

Certain areas of the brain and the functions such areas are involved with can be adversely affected by drug-related changes, over time.2 Thus motivation, memory, ability to think well, manage stress, and other basic life functions can be disrupted.2 These changes are only a few neurological risks that can be difficult to reverse and may present challenges long after a person stops using drugs.2

Heart and Cardiovascular System

Alcohol and several other types of drugs have dangerous effects on a person’s heart and cardiovascular system.6 Responsible for pumping blood and supplying oxygen to every part of the body, a threat to the cardiovascular system can have widespread effects.12 Commonly misused substances may speed or slow down heart rate, increase or decrease blood pressure, and increase the risk for life-threatening events such as stroke or heart attack.13

Liver and Kidneys

The liver and kidneys are two separate systems responsible for getting rid of toxins and waste products, maintaining important metabolic processes, balancing hormones and electrolytes, and other functions.14, 15 Continued or heavy alcohol use can cause liver disease or inflammation, leading to reduced function and increased cancer risk over time.6 Non-sterile injection of drugs may increase the risk of contracting hepatitis viruses, which can compound other substance-related liver injury.7

Cocaine, opioids, alcohol, and other substances can damage the kidneys through various mechanisms including impaired blood supply to the kidneys, scarring of delicate renal tissues, and other forms of renal injury that may progress to overall kidney failure.16

Lungs and Respiratory System

The lungs and respiratory system are responsible for oxygen delivery, air filtration, and the removal of carbon dioxide.17 Chronic alcohol or drug use can impair your immune system and make the lungs more vulnerable to infections (including pneumonia) and respiratory distress.6 Additionally, irritation and damage from smoking substances can cause scarring, a variety of lung diseases, and worsening asthma.1, 4, 7

Routes of Administration and Health Effects

The method of ingestion can significantly impact the health consequences of drugs or alcohol.1 People may choose different methods of administration to experience faster or stronger effects.18 Common methods of drug use include nasal insufflation or snorting, injecting a liquified form of the drug, and smoking the drug in various forms.4 Each method comes with its own consequences, but chronic drug use of any kind puts a person at risk for tolerance, physical dependence, and addiction.2, 4


Snorting involves inhaling a drug, such as cocaine, through the nasal canal.18 Repeated snorting of a drug may eventually lead to a perforated nasal septum, chronic bloody or runny noses, or difficult swallowing.18

Many drugs come in powdered form, making them easy to snort. But those that come as pills can also be snorted by crushing the pill or emptying the tablet.8 Commonly snorted drugs include cocaine, methamphetamine, heroin, and other opioids.8, 19


Injecting drugs intravenously can produce a relatively more rapid and intense high than some other methods of use such as oral consumption.18 But, it also increases your risk for serious health conditions and overdose.20 Shooting up, or intravenous injection, introduces the substance directly into the circulation, which can introduce pathogens into the bloodstream and lead to tissue inflammation and scarring.20 Scars, known as track marks, commonly occur on the inner arm where people usually start injecting.21 If the arms get too scarred or inflamed, other sites on the body may be used.21

Heroin, cocaine, and methamphetamine are some of the most commonly injected drugs, but other drugs can be dissolved and injected too.21 Non-sterile needle drug use puts a person at greater risk for HIV/AIDS, hepatitis, heart infections, skin infections, and overdose.20


Smoking both legal and illegal substances can cause dangerous long-term health effects.19 Substances can be smoked by rolling cigarettes or cigars from the dried leaves of a drug or dried leaves mixed with the powder of a drug or by inhaling the smoke while burning the drug.18, 19 Examples of drugs that are smoked include tobacco, marijuana, methamphetamine, cocaine, and many prescription drugs.19 Chronic cough, asthma, COPD, lung infections and pneumonia, and lung cancer are a few examples of health conditions that are directly caused by smoking.18, 19

Mental Health Effects of Addiction

Addiction and substance use can affect mental health.22 A substance use disorder is a type of mental health disorder (illness) that often co-occurs with other mental disorders.22 Whichever appears first, both substance misuse and mental health disorders can contribute to the worsening of the other.22 It can be difficult to discern which “came first,” so concurrent treatment is usually recommended.22

Substance use disorder, other mental health disorders, psychosocial disabilities, and other non-typical mental states are categorized together as mental health conditions.23 When people have multiple mental health conditions, they are said to have co-occurring disorders, or a dual diagnosis.24 In 2020, 17 million U.S. adults suffered from co-occurring mental illness and substance use disorder.24 In 2019, 970 million people worldwide were living with a mental disorder.23

Mental disorders that may occur alongside substance use disorder are anxiety disorders, bipolar disorder, depression, schizophrenia, PTSD, and others.23 In order to have the best chance at recovery, it is important to receive a diagnosis and an integrated treatment plan to simultaneously address both the substance use disorder and mental health issues.22

Getting Help

Substance use disorder is a pervasive disease that can affect several aspects of physical health and even be life-threatening.1 But, if it is ignored, it may also have negative repercussions for society or your relationships.1

Hope for recovery is available in the form of addiction treatment. Treatment may occur on an inpatient or outpatient basis, but usually involves behavioral therapy as its backbone.11 Medications may be administered during detox and in ongoing treatment, depending on the type of substance used.11

After an initial treatment program, diligent aftercare efforts can help people maintain recovery momentum. As part of these continuing care efforts, community-run programs like Alcoholics Anonymous (AA) and Narcotics Anonymous (NA) provide much needed support for ongoing recovery.11

Talking to your doctor or contacting a local treatment center is a good way to begin your recovery. If you or a loved one is struggling with addiction, it is never too late to get started. Your insurance coverage often includes substance use disorder treatment. Call today .

Was this page helpful?
Thank you for your feedback.

American Addiction Centers (AAC) is committed to delivering original, truthful, accurate, unbiased, and medically current information. We strive to create content that is clear, concise, and easy to understand.

Read our full editorial policy

While we are unable to respond to your feedback directly, we'll use this information to improve our online help.