Drug addiction is often referred to by clinicians as substance use disorder because the condition involves compulsive consumption of intoxicating substances, which often leads to physical tolerance and dependence on these drugs. Addiction is a disease of the brain, which changes how the reward center is stimulated and how neurotransmitters are released. With help, many people have overcome substance use disorders, but too many people are unable to get the help they need. Continuing to abuse drugs for many years leads to physical and mental damage. Depending on the type of drug a person abuses, different organ systems can be harmed; however, long-term addiction usually harms several organ systems.
Physical and Mental Damage from Drug Abuse
Intoxicating substances change how different organ systems function while the person is intoxicated. Over months or years, these changes may lead to illness or organ damage.
- Brain: Abusing any kind of drug stimulates the reward system, which releases dopamine and serotonin. Some drugs also release a third mood-changing neurotransmitter called norepinephrine, which is involved in the fight-or-flight response. Releasing neurotransmitters, or changing how they are absorbed, leads to an intense pleasurable euphoria. Some drugs relax the body while others create stimulation, but the euphoria is the experience people seek when they abuse substances. Over many years, changes to neurotransmitter release and absorption lead to structural changes in the brain, affecting cognition, memory, and mood. People who struggle with drug addiction often have trouble forming memories, thinking through scenarios, and may develop a mood disorder like depression or anxiety.
- Heart: Drugs greatly impact the cardiovascular system. Substances can increase or decrease heart rate and increase or decrease blood pressure; these changes may trigger an underlying heart condition, damage the walls of veins and arteries, or cause deterioration of the heart muscle itself. Some drugs can cause blood clots, which can lead to heart failure.
- Lungs: Drugs that are smoked or inhaled cause direct damage to the lungs, leading to an increased risk of infectious diseases like pneumonia, tuberculosis, or bronchitis. Smoking also causes long-term damage from a buildup of harmful chemicals and can cause emphysema, chronic obstructive pulmonary disease (COPD), and lung cancer. Other drugs indirectly affect the lungs by changing how fast a person breathes, which can lead to oxygen deprivation.
- Stomach and intestines: Many drugs cause nausea or vomiting as a side effect, and long-term, this can lead to gastroesophageal reflux disease (GERD), ulcers in the stomach and intestines, changes to metabolism, and even stomach cancer. Some drugs directly cause tissue decay while others lead to a buildup of gastric acid over time. Some drugs change how waste is processed in the intestines, leading to chronic diarrhea or constipation.
- Liver: Because the liver processes most of the substances that enter the body and breaks them down into different chemicals, this organ takes the brunt of the dangerous substances that are consumed. This is especially true when drugs are consumed orally. Drugs can cause acute liver damage, leading to failure, cirrhosis, or liver cancer. Injection drugs also put the liver at risk, as they increase the chance a person will contract a viral infection that could harm the liver, like hepatitis B or C.
- Kidneys: The kidneys also filer toxins out of the body, especially when the liver does not break down some toxins. Often, liver damage and kidney damage are linked; if the liver fails at its job, the kidneys take over. Some drugs may indirectly lead to kidney damage by causing a condition called rhabdomyolysis, in which the skeletal muscles break down and the kidneys are unable to filter out all of the released toxins. Drugs that cause high blood pressure can also harm the kidneys. Toxins that are not consumed orally may filter through the kidneys instead of the liver, leading to direct damage.
Socially, long-term substance abuse can lead to financial problems through unemployment or spending too much money acquiring drugs illegally. Drug addiction can also change a person’s relationship to friends and family because the individual may focus more on consuming illicit substances than on spending time with loved ones.
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Harm Caused by Specific Drugs
Long-term drug addiction usually leads to damage in several parts of the body, but specific drugs cause slightly different types of long-term damage. Some of the most abused drugs in the US and the changes they cause to the body and mind over time are outlined below.
- Alcohol: Excessive alcohol consumption, whether it is from alcohol use disorder, binge drinking, or heavy drinking, led to the deaths of 88,000 people between 2006 and 2010, according to the Centers for Disease Control and Prevention (CDC). The National Institute on Alcohol Abuse and Alcoholism (NIAAA) reported that, in 2015, just over 56 percent of survey respondents reported consuming alcohol in the past month, indicating that over half the US population, ages 18 and older, drinks consistently.
Alcohol can damage several parts of the body, like the heart, leading to arrhythmias, cardiomyopathy (drooping heart muscle), high blood pressure, and stroke. People who drink too much alcohol may develop chronic pancreatitis, which develops over years, but symptoms may appear suddenly, especially serious weight loss from inability to absorb nutrients from food. Alcohol damages the liver, which processes ethanol directly; harm can come from fatty liver disease, alcoholic hepatitis, cirrhosis, and liver cancer.
Consuming too much alcohol changes how the brain functions, which may lead to trouble with memory, or mood disorders like depression and anxiety. Loss of thiamine from consuming too much alcohol can cause Wernicke-Korsakoff syndrome, which can cause confusion, dementia-like symptoms, tremors, and even paralysis. Long-term alcohol consumption increases the risk of several types of cancer, including stomach, liver, and breast cancer.
- Opioids: Addiction to opioid drugs is a serious epidemic in the United States, which began with less stringent prescribing practices around narcotic painkillers around 2000. The CDC found that over 1,000 people are sent to the emergency room due to opioid overdoses every day, and 91 people die from these overdoses. More people are turning to heroin because it is harder to get prescription narcotics like OxyContin or Vicodin. Physical dependence, tolerance, and addiction are long-term risks associated with opioid consumption, and overdosing on these drugs is becoming more common, as stronger opioids like fentanyl make their way into the black market.
Opioids affect breathing rate, so people who take too large a dose of narcotics may suffer very shallow or irregular breathing, or they may stop breathing. Oxygen deprivation is a long-term problem as well as an acute problem; lack of oxygen harms all other organ systems in the body. Long-term, the body becomes more sensitive to pain since opioids change how the brain processes this sensation; this can cause hyperalgesia, or an increased experience of pain when the person is not intoxicated from opioids. Chronic constipation can lead to gastrointestinal damage and bleeding.
- Benzodiazepines: These sedatives, which include Valium, Xanax, and Klonopin, were developed to help people who struggle with anxiety and panic disorders, and they can also be used to treat seizure disorders. Some benzodiazepines may be used to ease people struggling with alcohol use disorder off physical dependence on alcohol. However, the drugs themselves are also addictive. The body rapidly develops a tolerance to these substances, so mental health professionals do not prescribe them for more than two weeks of regular use.
If a person develops an addiction to these drugs, withdrawal symptoms typically mirror the condition they treated – increased panic attacks and insomnia, predominantly. People who abuse benzodiazepines and did not have a pre-existing anxiety condition are more likely to develop this mood disorder due to drug abuse. Benzodiazepines also lead to cognitive decline and memory damage. The person may also develop muscle weakness, lowered immune system function, harm from low blood pressure, and a reduced breathing rate.
- Cocaine: This is an intense stimulant drug that can quickly cause addiction and may lead to several acute effects like a heart attack or heart failure, stroke, seizure, and even psychosis. Long-term, a person struggling with cocaine addiction may experience insomnia and psychosis from repeated cocaine binges. Snorting the drug can cause damage to the nasal passages, upper palate, and throat, leading to septal or palate perforation; smoking crack cocaine causes lung damage, increasing the risk of respiratory infection. The drug reduces blood flow to several parts of the body, which can cause ulceration and tissue loss in the intestines; high blood pressure caused by the abuse damages kidney function.
Consuming cocaine with alcohol, which is a common form of polydrug abuse, causes the liver to produce cocaethylene, a harmful chemical that increases the risk of liver damage. The risk of stroke, seizures, aneurysm, and brain hemorrhages increases, and the person is more likely to struggle with intense mood disorders, memory loss, and a decline in cognitive function.
- Methamphetamines: Like cocaine, meth is a potent stimulant drug that can cause acute harm, including meth binges called tweaking, hallucinations, and psychotic breaks. Long-term damage from meth abuse is extensive. Rotting teeth, from chronic dry mouth, is one of the most common symptoms. The drug also triggers chronic depression and anxiety, and may trigger psychosis. The cardiovascular system, gastrointestinal system, liver, and kidneys are all damaged from processing toxins and chronic high blood pressure.
The person may experience hallucinations about insects on them or develop skin-crawling sensations; they often pick at their skin, leading to long-term skin damage and infections. They can develop lung damage from smoking or infections from intravenous injection with unclean needles.
- Marijuana: As more states pass medical and recreational marijuana legislation, it is important to understand this drug in terms of its addictiveness, whether it is legal or not. People who begin abusing marijuana at a young age and continue through adulthood are more likely to suffer cognitive decline and memory damage. Some structures in the brain shrink, so there is a loss of grey matter in areas involving memory, planning, and reasoning.
Smoking or vaping marijuana can damage the lungs, much like smoking cigarettes or using e-cigarettes. Changes to oxygen intake from smoking, as well as high blood pressure, can cause damage to other organ systems. Marijuana increases a person’s risk of certain cancers, including head, neck, and bladder cancers.
- MDMA/Molly/Ecstasy: This is one of the most widely consumed designer drugs or totally synthetic drugs. It is often found in clubs or raves, where it is shared socially. Using MDMA or derivatives consistently can dramatically change how dopamine is processed in the brain, so the person will experience intense depression as a withdrawal symptom.
The drug shrinks the hippocampus region of the brain, which is linked to cognitive impairment and decline. People who abuse MDMA for a long time experience sleep disorders, trouble with reasoning and impulsiveness, anxiety, and confusion. The drug is also associated with dehydration, and over time, mild dehydration can damage the liver and kidneys. As a stimulant, MDMA or ecstasy can increase a person’s heart rate, and over time, this can lead to damage to the heart muscle, blood clots, and permanent high blood pressure.
Effects May Reverse if Drug Addiction Ends
Although some long-term effects from drug addiction may remain and require treatment, many of these ailments can be reversed if the person overcomes their addiction. This requires a lot of help from medical professionals, evidence-based rehabilitation, therapy, and loved ones. Fortunately, this help is available, and full recovery is possible.