Why an Opiate's Impact on the Brain Can Cause Addiction

Five pills of OXYCOCONE.
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Opiates are a type of narcotic drug that acts as depressants on the central nervous system (CNS). Opiates come from opium, which can be produced naturally from poppy plants or derived from semi-synthetic alkaloids.

Some of the most common opiates include:

  • Prescription painkillers
  • Morphine (Kadian, Avinza)
  • Codeine
  • Hydrocodone (Vicodin)
  • Oxycodone (OxyContin, Percocet)
  • Heroin

Statistics on Use and Abuse

Opiate use is on the rise globally, so it may come as no surprise that abuse and addiction to such substances have also increased in recent years. According to the National Institute on Drug Abuse:

  • In 2013, opiate painkillers were prescribed more than 200 million times.
  • Between 26 and 36 million people worldwide abuse opiates.
  • Over two million adults in the United States suffer from substance abuse problems related to the abuse of opiate painkillers.
  • Nearly half a million U.S. adults are addicted to heroin.
  • In 2010, the overuse of opiate painkillers resulted in nearly 17,000 deaths in the United States.
  • The American Society of Addiction Medicine reports that about 75 percent of all people suffering from opioid addiction disease end up switching to heroin as a cheaper source of opiates.

How Opiates Affect the Brain

Both humans and animals have opiate receptors in the brain. These receptors act as action sites for different types of opiates such as heroin and morphine.

The reason the brain has these receptor sites is because of the existence of endogenous (internal) neurotransmitters that act on these receptor sites and produce responses in the body that are similar to those of opiate drugs.

Opiates work by binding to specific receptors in the brain, thus mimicking the effects of pain-relieving chemicals that are produced naturally. These drugs bind to opiate receptors in the brain, spinal cord, and other locations in the body. By binding to these receptors, they block the perception of pain. Opiates can block pain and cause feelings of well-being, but they can also cause side effects such as nausea, confusion, and drowsiness.

In addition to relieving pain, opiates can lead to feelings of euphoria. While they are often very effective in treating pain, people can eventually develop a tolerance for these drugs, so they require higher doses to achieve the same effects. As the effects of opiate drugs become more tolerated, people may begin taking increasingly higher doses to experience the same pain-relieving effects and to reduce symptoms of withdrawal. Symptoms of opiate withdrawal can include anxiety, muscle aches, irritability, insomnia, runny nose, nausea, vomiting, and abdominal cramping.

What makes prescription opiates so potentially dangerous? Because they impact the brain much in the same way as heroin and morphine, they present a risk of addiction, overuse, and overdose. Some people can even become addicted when taking them exactly as prescribed, but the dangers can be increased by not taking them as directed or by combining them with other substances including alcohol and other drugs.

An estimated 100 million adults in the U.S. suffer from some type of chronic pain. Opioid pain relievers are often prescribed to treat injury-related pain, dental pain, and back pain. Research suggests that when taken as directed, they are not likely to lead to overuse or addiction.

People who use opiates to control pain should contact their health care professional if they believe that they may be developing a tolerance or addiction.

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Article Sources

  • American Society of Addition Medicine. (2015). Opioid addiction disease: 2015 facts and figures.

  • Volkow, N.D. (2014). America's addiction to opioids: Heroin and prescription drug abuse. Testimony to Congress. National Institute on Drug Abuse.