How Does Heroin Affect the Brain and Body?

Heroin is a highly addictive opioid drug made from morphine. Recreational users value the drug for its euphoric and pain-blocking effects, but heroin has no legitimate medical use. Heroin is an extremely dangerous drug that can permanently damage the brain and body and cause death.

Overdose deaths linked to heroin and other opioids continue to surge in the U.S. The 2020 National Survey on Drug Use and Health and the Centers for Disease Control and Prevention (CDC) report the following statistics for 2020.

• Almost one million Americans aged 12 or older reported using heroin in the past 12 months.
• Almost 700,000 Americans aged 12 or older had a heroin use disorder (addiction).
• Almost 70,000 Americans died from an opioid overdose.
• About 13,165 people died from an overdose involving heroin.

Why is Heroin So Addictive?

Researchers believe opioids like heroin are so addictive because they interfere with and alter the normal function of the brain’s motivation and reward system. Heroin use spikes levels of hormones like dopamine which increase the pleasure response, causing the user to feel an intense sense of happiness and relaxation.

Although the brain naturally increases dopamine levels in response to a pleasurable experience, heroin triggers unnaturally high levels of the chemical. Each time a person takes the drug, the brain reinforces the behavior and strengthens the user’s motivation to repeat the experience. Eventually, the brain rewires itself to the point it is unable to deliver pleasure without the drug.

As the user continues taking heroin, their body builds up a “tolerance” to the usual dose, demanding a higher amount to deliver the desired effects. When the user needs higher doses to get the impact they once achieved with a lower dose, it signals their body has physically adapted to the drug’s presence. If an individual stops using a drug once physical dependence has taken hold, they will experience withdrawal symptoms.

Withdrawal symptoms occur because heroin use creates an imbalance in the brain, and when drug use abruptly stops, the brain is thrown into a hyperactive state as it struggles to recover balance. Uncomfortable, sometimes severe, withdrawal symptoms occur until the brain regains equilibrium.

Tolerance is the first step to dependence and addiction. At this point, it is very challenging for a person to stop using heroin without professional assistance.

How Heroin Affects the Brain and Body

Short-term effects

When a person injects, smokes, or snorts heroin, the drug quickly enters the areas of the brain regulating pleasure, sleep, pain perception, and life-sustaining functions like heart rate and breathing. Users report an almost immediate rush of euphoria, followed by heaviness in the extremities and a dream-like semiconsciousness. Because the chemical makeup of heroin mimics endorphins, which naturally block pain and lift the mood, the drug also dulls pain perception and reduces anxiety.
Heroin is a depressant, meaning it slows vital functions of the brain that control breathing. As dangerous as heroin is, it is even more dangerous if taken with other depressants, like alcohol or benzodiazepines.

The National Institute on Drug Abuse (NIDA) states the short-term effects of heroin include:

• Warm flushing of the skin, dry mouth
• Nausea, vomiting
• Severe itching
• Drowsiness lasting several hours
• Cloudy thinking
• Slowing of heart function and breathing

Heart rate, blood pressure, and breathing can slow to life-threatening levels, increasing the risk of heart failure, coma, permanent brain damage, and death.

Long-term effects

Multiple research studies have found regular heroin use causes the brain’s white matter to deteriorate, contributing to impaired decision making, lack of good judgment, difficulty handling stress, and poor impulse control. Impaired cognitive functioning puts heroin users at an increased risk for severe depression, risky decisions, and suicide. Damage to the brain may be irreversible.

According to NIDA, long-term effects of heroin may include:

• Imbalance in neuronal and hormonal systems
• Deterioration of the brain’s white matter, affecting decision-making abilities
• Difficulty regulating behavior, especially in response to stressful situations
• Increased risk of mental disorders, including depression and antisocial personality disorder
• Chronic insomnia
• Sexual dysfunction in men
• Irregular menstrual cycle in women

Additional risks are associated with the method of use

• Injecting heroin increases the user’s risk of contracting a blood-borne disease like HIV, Hepatitis B and C, scarred or collapsed veins, skin abscesses, and bacterial infections of the blood vessels and heart valves.
• Snorting heroin may damage nasal passages and cause a perforation of the nasal septum.
• Smoking heroin can cause severe lung damage and oral problems.

Organs and body systems affected by long-term heroin use

Over time, heroin weakens the immune system and may severely damage multiple life-sustaining organs and functions of the body.

Long-term use results in the following.

• Suppress autonomic functions such as breathing, heart rate, and temperature. Using heroin just one time can slow breathing enough to cause death. The longer heroin use continues, the greater the risk of heroin-induced death.
• Damage to the brain stem, which controls the motor and sensory systems, and regulation of cardiac and respiratory function, consciousness, and the sleep cycle.
• Damage to the cerebral cortex, which regulates cognitive processes, including decision-making and problem-solving.
• Damage to veins can adversely affect organs and increase the risk of stroke.
• Cause an infection of the heart lining and valves or trigger abnormal heart rhythm, increasing the risk of a heart attack.
• Cause a fluid build-up in the lungs, leading to shortness of breath and breathing problems. Lung dysfunction increases the risk of pneumonia and tuberculosis.
• Damage to the liver can result in chronic liver disease or liver cancer.
• Damage to fetal development in pregnant women can result in fetal death, neonatal abstinence syndrome (NAS), and withdrawal symptoms in infants after birth. Children of women who use heroin during pregnancy have a high risk of physical and behavioral problems and can experience life-long cognitive deficits.

A person can die the first time they use heroin. There is no way for a person buying illicit heroin to know what the product contains. Statistics link heroin containing fentanyl, a drug so potent even the smallest amount can cause death, to many fatal overdoses. The longer a person continues to use heroin, the greater their risk of dying from the devastating effects heroin has on the body and brain.

Contact Midwest Recovery Centers to learn how we can help you detox and recover safely and comfortably from heroin use.

Reviewed and Assessed by
Taylor Brown, B.A.Com., CADC
Tim Coleman, M. of Ed.