Opioids' influence on the brain: an explanation
In the United States, an estimated 2.7 million people have grappled with opioid use disorder within the past 12 months [1]. Opioids, a class of drugs that attach to opioid receptors in the brain and other parts of the body, encompass a wide range of substances, including synthetic and natural opioids.
Synthetic opioids, created in a lab while also using natural opioids, include hydrocodone, oxycodone, oxymorphone, and hydromorphone. There are also synthetic opioids with chemical structures similar to fentanyl, such as acetyl fentanyl, butyryl fentanyl, furanyl fentanyl, and beta-hydroxythiofentanyl. Heroin, a highly addictive drug made from morphine, is an illegal opioid.
Long-term opioid use can lead to several troubling consequences, including cognitive decline and changes in brain structure. Chronic opioid exposure can result in a faster decline in verbal fluency and increase the risk of mild cognitive impairment (MCI), particularly amnestic MCI, which involves memory loss [1].
Brain scans reveal a reduced volume in certain areas of the brain due to long-term opioid use [2]. This reduction is associated with deficits in learning, judgment, decision-making, memory retention, and behavioral regulation. Chronic opioid use also disrupts neurotransmitter systems, such as dopamine pathways, leading to impaired learning capacity, decision-making, and heightened impulsivity and stress sensitivity [2].
These cognitive impairments and brain alterations contribute to the chronic and relapsing nature of opioid use disorder, making treatment and recovery more challenging [3].
SAMHSA (Substance Abuse and Mental Health Services Administration) offers resources for people seeking help for opioid misuse or addiction. These resources include a free 24/7 National Helpline (800-662-HELP), Opioid Treatment Program Directory, Substance Use Treatment Locator, and Behavioral Health Treatment Services Locator [4].
Treatment of opioid misuse may involve medication-assisted therapy using drugs that bind to the same opioid receptors in the brain. Medication-assisted treatment options for opioid use disorder include methadone, buprenorphine, and naltrexone [5].
Opioids have short-term effects like pain relief, euphoria, suppressed breathing, drowsiness, dizziness, and suppressed conscious reasoning and awareness. However, repeated use of opioids can cause dependence and addiction. Dependence refers to repeated use causing nerve cell activity changes, leading to withdrawal symptoms when the drug is stopped. Addiction results from long-term use, causing an uncontrollable desire to continue using opioids despite adverse effects [6].
In natural opioids, morphine is used for pain treatment, while codeine is used for pain and cough suppression. Opioids also include drugs like fentanyl (for severe pain), methadone (for opioid use disorder), and tramadol (for moderate to moderately severe pain) [7].
Understanding the impact of long-term opioid use on cognitive functions and brain structure is crucial for developing effective treatments and supporting those struggling with opioid use disorder on their journey to recovery.
References:
[1] National Institute on Drug Abuse. (2020). Opioid Overdose Crisis. Retrieved from https://www.drugabuse.gov/drugs-abuse/opioids/opioid-overdose-crisis
[2] Volkow, N. D., Fowler, J. S., & Wang, G. J. (2017). The neurobiology of opioid addiction. Nature Reviews Neuroscience, 18(12), 707-720.
[3] National Institute on Drug Abuse. (2020). Principles of Drug Addiction Treatment: A Research-Based Guide. Retrieved from https://www.drugabuse.gov/publications/principles-drug-addiction-treatment-research-based-guide/principles-effective-treatment
[4] Substance Abuse and Mental Health Services Administration. (n.d.). SAMHSA's National Helpline. Retrieved from https://www.samhsa.gov/find-help/national-helpline
[5] Substance Abuse and Mental Health Services Administration. (2020). Medication-Assisted Treatment (MAT). Retrieved from https://www.samhsa.gov/medication-assisted-treatment
[6] National Institute on Drug Abuse. (2020). What are opioids? Retrieved from https://www.drugabuse.gov/publications/drugfacts/opioids
[7] National Institute on Drug Abuse. (2020). Opioids: Prescription, Abuse, Addiction. Retrieved from https://www.drugabuse.gov/publications/drugfacts/opioids
- The reduced brain volume due to long-term opioid use is associated with various cognitive deficits, such as deficits in learning, judgment, and behavioral regulation, which predictively contribute to the uncontrollable desire for continued opioid use, a hallmark of addiction.
- In health-and-wellness circles, scrutiny regarding obesity and its associated medical-conditions needs to actively expand to include the potential long-term cognitive repercussions of opioid use, considering the link between chronic opioid use and mild cognitive impairment.
- Following the cognitive impairments associated with long-term opioid use, science must continue to advance in understanding the mechanistic underpinnings of how these drugs alter the brain's structure and function, with the aim of developing predictive models for identifying individuals at risk of developing addiction.
