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Drugs: How Drugs and Alcohol Decrease Your Immune Function

When we talk about the negative effects of addictive substances, the problem is so all-encompassing that we ignore their effects on the immune system. The science behind addiction and its destructive consequences has been clear for many years. We know alcoholism can lead to liver failure. We know that heroin and other opiates cause the brain and its ability to make rational decisions to deteriorate. But one aspect of drug use and addiction that is less studied and understood is their effects on the body’s immune function and response to infection.  Because the primary symptoms of drugs such as meth and cocaine are so pronounced, we sometimes overlook this more insidious issue: addiction makes the body more susceptible to illness and infection. Worse, few addictions exist that do not cause lasting harm to the body’s immune system.

The Basics of Proper Immune Function

While the human body is incapable of producing all of the substances necessary for survival, it is very particular about when and where those external substances are used. The body has two distinct but intertwined immune response systems: an innate system and an adaptive system. The innate or non-specific immune system defends against anything deemed dangerous, such as microorganisms that enter through the skin and digestive tract. When a foreign microbe enters the body through an open wound, for example, an immune response is activated when it interacts with certain cells. Antigens are then formed by the body, emergency cells that both attack the substance and learn its structure which enables future antigens to respond more efficiently. The adaptive system takes the information gained from these intrusions, providing immunities and resistances over time. This system makes vaccination possible as we allow our bodies to fight illnesses such as polio and measles without encountering a dangerous and active version of such viruses.

The Effects of Hard Drugs

While drugs all cause harm in their own unique ways, the primary reason drugs are capable of destroying immune function is due to the damage they cause to internal organs and other structures in the body.

Opiates and Immunodeficiency

Although most of us like to avoid pain, the proper function of your body’s pain receptors is vital to the quality of your life. In basic terms, pain is the body’s way of communicating that something is wrong. Opiates such as morphine, opium, and oxycodone block your nervous system from sending these signals to the brain. The addiction created by opiates is a terrible double-edged sword: while the body may cease feeling pain while the drug is active, the body will begin to require an ever-increasing amount of painkillers to maintain the effect. The downsides of ignoring pain are fairly obvious. What is less obvious is the effect opiates eventually have on lung and digestive tissue. Long-term opiate use (particularly for those who inject the drug) has been shown to cause staph infections, pneumonia, hepatitis, and related bone infections. As the article from the US National Library of Medicine notes, however, it is unclear whether these conditions are caused solely by drug use, poor decision-making such as unsafe sex and using contaminated needles, or both.


When the use of heroin became widespread in the 1970s, its effects on immune function quickly became apparent as the rate of endocarditis and kidney disease cases dramatically rose. The connection was confirmed when studies revealed that long-term heroin use triggered an equally long-term inflammatory response in the bodies of those addicted to the substance.  Inflammation is the body’s natural signal for its cells to defend against foreign substances and begin to process of healing. The toxins produced by heroin force the body to remain permanently inflamed, exhausting the body’s resources to fight real threats like viral and bacterial infections. Heroin can even cause a permanent change in the body’s proper cellular function, which can lead to some forms of cancer.


Meth is much like cocaine in the way they stimulate the nervous system and induce a release of positive chemicals like serotonin, adrenaline, and dopamine. Unlike cocaine that only lasts a few minutes, however, the rush of meth can last for hours; the addictive nature of meth can hardly be understated. While its effect on the nervous system is understood, only recently has its effect on organs and systems such as the liver, kidneys, blood cells, and skin been studied. Essentially, meth increases the alkalinity of the body, reducing the effectiveness of innate immune function. 

Recreational Substances, Recreational Infections

So-called “recreational” drugs have become increasingly popular in the United States, aided by the legalization of marijuana in several states as well as the decriminalization of cocaine in Oregon in 2020. Despite this (or because of the availability of hospitalizations and treatment), evidence continues to pile up on the long-term effects of recreational drugs.

Cannabis and Vulnerability to Viral Infection

Marijuana is one of the most used recreational substances in the world, with more than 188 million users. This number increases by two to three million annually. From a study published in June 2021 by researchers from the George Washington University in Washington D.C. and the Nation Institute of Drug Abuse, users who smoke marijuana are more susceptible to chronic pulmonary illnesses and poor liver function. They conclude that further research is necessary to investigate whether regular marijuana use merely made infections more likely or caused them to worsen.

Alcohol Affects More Than Just the Liver

Because of its availability and regularity in the lives of millions in the U.S. alone, alcohol is rarely seen as a drug. Alcoholism, however, is widely and rightly recognized as a terrible addiction, with more than 16 million Americans being reported as suffering from an alcohol use disorder. Alcohol primarily interferes with the delicate biome that exists inside the stomach and digestive tract, causing bacteria to multiply. Alcohol also serves to erode the cells within the GI tract, allowing the increased bacterial load to filter into the body, more particularly inside the liver. These microorganisms then cause infections, resulting in constant inflammation and a decreased ability for the body’s immune function to perform effectively. With enough time, the irreversible effects of alcohol on the body’s immune system can result in viral hepatitis, cancer, and total liver failure. The serious nature of alcoholism and its effects on the liver is the number one reason for necessary liver transplants in the United States.

Drugs, Alcohol, and COVID-19

The viral pandemic of COVID-19 has presented a tremendous threat to those addicted to drugs and alcohol. The consequences of the outbreak reach much farther than the disease itself. The American Medical Association announced in September 2021 that every state in the U.S has seen a spike in overdose deaths, and many more will see complications due to the increased use of illicit substances (particularly fentanyl). The rise of medical complications stemming from these issues has only added to the burden already felt by hospitals and clinics nationwide. While the long-term effects of the COVID pandemic in relation to increased drug use and illness are yet to be determined, we can only hope for a brighter outcome than expected.

Contact Ardú Recovery Center in Provo, Utah, and Free Yourself from Addiction

Addiction affects almost every aspect of life, from psychological and mental, to spiritual and physical. Before you or someone you love suffers from the illnesses that accompany alcoholism and constant drug use, contact Ardú Recovery Center. With a combination of medical and holistic treatments, we can help you rediscover true wellness.