The brain can be severely damaged by the use of opiates. Learn about the different ways the brain is impacted by the short- and long-term consumption of opiates.

While opiates can be helpful or necessary in certain medical conditions, they have short- and long-term effects on the brain’s structure and chemistry.

Short-term, opiates produce their intended results by providing pain relief but also triggering the body’s natural rewards system. This positive feeling associated with the drug’s use causes people to seek that feeling again by taking more of the medication. The addictive properties of opiates result from this positive association. The depressant effects of opiates can also cause mental fogging and tiredness.

Long-term opiate use can lead to additional negative consequences. As the opiate receptors in the brain are consistently activated, it takes more of the drug to have the original, intended effect. This necessary increase is due to drug tolerance developing. Long-term opiate use can also destroy brain cells and reduce the overall mass of the brain, leading to difficulty with reasoning or thinking.

Short-Term Effects: Opiates and the Brain

Even if a person never took an opiate, the effects of opiates are still felt. Brains produce very small amounts of opiates naturally. When opiate receptors in the brain are activated, dopamine releases and the rewards system is triggered. Opiates produced by the body, such as endorphins, are responsible for the good feeling of a runner’s high or eating chocolate. Opiate drugs produce similar effects to the naturally produced chemicals but are much more potent.

Short-term effects of opiates on the brain include:

  • Addiction
  • Pain relief
  • Feelings of well-being
  • Tiredness
  • Mental clouding
  • Slowing of the respiratory center

When opiate receptors are activated, dopamine is released which activates the reward system and provides a sense of well-being. Because humans are biologically driven to activate the rewards system to remain alive, we unconsciously seek out activities that activate it. In drug use, it leads us to continue seeking the drug again and again without consciously thinking about it. Even short-term use of an opiate can lead to addiction.

Opiates also slow down the central nervous system, including the brain. This slowing causes the depressant effects of opiates, like tiredness and confusion. The degree of confusion differs from person to person and is also dependent on the dose of the opiate. The effects of opiates may range from slight inattention to disorientation or memory loss.

At high doses, opiates target the respiratory center in the brain. Opiates can lead to slow or shallow breathing known as respiratory depression, which can lead to death.

Long-Term Effects: Opiates and the Brain

Long-term effects of opiate use stem from repeated stimulation of opiate receptors.

Long-term effects of opiates on the brain include:

  • Reduction in brain mass
  • Death of brain cells
  • Permanent difficulty thinking or reasoning
  • Tolerance, dependence, and addiction

Research studies have shown that even after just a month of using morphine, people experienced measurable changes in their brains. MRIs showed that patients who took morphine had a reduction in gray matter volume throughout the study. These reductions were focused on the parts of the brain responsible for the regulation of cravings, pain, and emotions.

Consistent use of high-dose opiates is also associated with the destruction of a part of the brain cell called the dendritic spine. When these spines disappear, brain cells have difficulty communicating with one another, leading to difficulty with thinking and reasoning.

Like short-term use of opiates, long-term use can also lead to addiction. As opioid addiction progresses, the reward system is thrown further off balance, resulting in intense cravings. There is then an even more intense drive to seek the positive feeling associated with opiate use. Additionally, with the destruction of brain cells and brain matter, it can be even harder to resist the cravings.

Long-term use is also associated with developing an opiate tolerance. People’s bodies eventually adapt to the constant supply of opiates and become physically dependent on it. If opiate consumption stops, opioid withdrawal symptoms like intense shaking, sweating, vomiting or headaches occur.

Key Points: Opiates and the Brain

Opiates can affect the brain following short- and long-term use. Here are a few key points to remember when thinking of how opiates affect the brain:

  • Addiction can develop from both short- and long-term opiate use
  • Opiates cause a release of dopamine and activate the rewards system of the brain
  • Positive effects of opiate use include:
    • Pain reduction
    • A sense of well-being
  • Negative effects of opiate use include:
    • The destruction of brain cells and brain mass
    • Difficulty thinking or reasoning

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Editor – Thomas Christiansen
With over a decade of content experience, Tom produces and edits research articles, news and blog posts produced for Advanced Recovery Systems. Read more
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Medically Reviewed By – Nathan Jakowski, PharmD
Nate Jakowski is a clinical pharmacist specializing in drug information and managed care. He completed his Doctor of Pharmacy degree at the University of Wisconsin. Read more
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Liao, Dezhi. “Mu-opioid receptors modulate the stabili[…] of dendritic spines.” January 19, 2005. Accessed May 10, 2019.

Kosten, Thomas, George, Tony. “The Neurobiology of Opioid Dependence: I[…]ations for Treatment.” July 2002. Accessed May 10, 2019.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.