The Science of Drug Abuse & Addiction
What are the immediate (short-term) effects of heroin use?
Once heroin enters the brain, it is converted to morphine and binds rapidly to opioid receptors.11 Abusers typically report feeling a surge of pleasurable sensation—a “rush.” The intensity of the rush is a function of how much drug is taken and how rapidly the drug enters the brain and binds to the opioid receptors. With heroin, the rush is usually accompanied by a warm flushing of the skin, dry mouth, and a heavy feeling in the extremities, which may be accompanied by nausea, vomiting, and severe itching. After the initial effects, users usually will be drowsy for several hours; mental function is clouded; heart function slows; and breathing is also severely slowed, sometimes enough to be life-threatening. Slowed breathing can also lead to coma and permanent brain damage.12
Opioids Act on Many Places in the Brain and Nervous System
Opioids can block pain messages transmitted through the spinal cord from the body.
What are the long-term effects of heroin use?
Repeated heroin use changes the physical structure13 and physiology of the brain, creating long-term imbalances in neuronal and hormonal systems that are not easily reversed.14,15 Studies have shown some deterioration of the brain’s white matter due to heroin use, which may affect decision-making abilities, the ability to regulate behavior, and responses to stressful situations.16-18 Heroin also produces profound degrees of tolerance and physical dependence. Tolerance occurs when more and more of the drug is required to achieve the same effects. With physical dependence, the body adapts to the presence of the drug and withdrawal symptoms occur if use is reduced abruptly. Withdrawal may occur within a few hours after the last time the drug is taken. Symptoms of withdrawal include restlessness, muscle and bone pain, insomnia, diarrhea, vomiting, cold flashes with goose bumps (“cold turkey”), and leg movements. Major withdrawal symptoms peak between 24–48 hours after the last dose of heroin and subside after about a week. However, some people have shown persistent withdrawal signs for many months. Finally, repeated heroin use often results in addiction—a chronic relapsing disease that goes beyond physical dependence and is characterized by uncontrollable drug-seeking no matter the consequences.19 Heroin is extremely addictive no matter how it is administered, although
routes of administration that allow it to reach the brain the fastest (i.e., injection and smoking) increase the risk of addiction. Once a person becomes addicted to heroin, seeking and using the drug becomes their primary purpose in life.
Why does heroin use create special risk for contracting HIV/AIDS and hepatitis B and C?
Heroin use increases the risk of being exposed to HIV, viral hepatitis, and other infectious agents through contact with infected blood or body fluids (e.g., semen, saliva) that results from the sharing of syringes and injection paraphernalia that have been used by infected individuals or through unprotected sexual contact with an infected person. Snorting or smoking does not eliminate the risk of infectious disease like hepatitis and HIV/AIDS because people under the influence of drugs still engage in risky sexual and other behaviors that can expose them to these diseases.
Injection drug users (IDUs) are the highest-risk group for acquiring hepatitis C (HCV) infection and continue to drive the escalating HCV epidemic: Each IDU infected with HCV is likely to infect 20 other people.21 Of the 17,000 new HCV infections occurring in the United States in 2010, over half (53 percent) were among IDUs.22 Hepatitis B (HBV) infection in IDUs was reported to be as high as 20 percent in the United States in 2010,23 which is particularly disheartening since an effective vaccine that protects against HBV infection is available. There is currently no vaccine available to protect against HCV infection.
Drug use, viral hepatitis and other infectious diseases, mental illnesses, social dysfunctions, and stigma are often co-occuring conditions that affect one another, creating more complex health challenges that require comprehensive treatment plans tailored to meet all of a patient’s needs. For example, NIDA-funded research has found that drug abuse treatment along with HIV prevention and community-based outreach programs can help people who use drugs change the behaviors that put them at risk for contracting HIV and other infectious diseases. They can reduce drug use and drug-related risk behaviors such as needle sharing and unsafe sexual practices and, in turn, reduce the risk of exposure to HIV/AIDS and other infectious diseases. Only through coordinated utilization of effective antiviral therapies coupled with treatm
What are the treatments for heroin addiction?
A variety of effective treatments are available for heroin addiction, including both behavioral and pharmacological (medications). Both approaches help to restore a degree of normalcy to brain function and behavior, resulting in increased employment rates and lower risk of HIV and other diseases and criminal behavior. Although behavioral and pharmacologic treatments can be extremely useful when utilized alone, research shows that for some people, integrating both types of treatments is the most effective approach
Pharmacological Treatment (Medications)
Scientific research has established that pharmacological treatment of opioid addiction increases retention in treatment programs and decreases drug use, infectious disease transmission, and criminal activity.
When people addicted to opioids first quit, they undergo withdrawal symptoms (pain, diarrhea, nausea, and vomiting), which may be severe. Medications can be helpful in this detoxification stage to ease craving and other physical symptoms, which often prompt a person to relapse. While not a treatment for addiction itself, detoxification is a useful first step when it is followed by some form of evidence-based treatment.
Medications developed to treat opioid addiction work through the same opioid receptors as the addictive drug, but are safer and less likely to produce the harmful behaviors that characterize addiction. Three types of medications include: (1) agonists, which activate opioid receptors; (2) partial agonists, which also activate opioid receptors but produce a smaller response; and (3) antagonists, which block the receptor and interfere with the rewarding effects of opioids. A particular medication is used based on a patient’s specific medical needs and other factors. Effective medications include:
Naltrexone (Depade® or Revia®) is an opioid antagonist. Naltrexone blocks the action of opioids, is not addictive or sedating, and does not result in physical dependence; however, patients often have trouble complying with the treatment, and this has limited its effectiveness. An injectable long-acting formulation of naltrexone (Vivitrol®) recently received FDA approval for treating opioid addiction. Administered once a month, Vivitrol® may improve compliance by eliminating the need for daily dosing.
The many effective behavioral treatments available for heroin addiction can be delivered in outpatient and residential settings. Approaches such as contingency management and cognitive-behavioral therapy have been shown to effectively treat heroin addiction, especially when applied in concert with medications. Contingency management uses a voucher-based system in which patients earn “points” based on negative drug tests, which they can exchange for items that encourage healthy living. Cognitive-behavioral therapy is designed to help modify the patient’s expectations and behaviors related to drug use and to increase skills in coping with various life stressors. An important task is to match the best treatment approach to meet the particular needs of the patient.