Trial reportPain medicine (Malden, Mass.)2016
One Month of Oral Morphine Decreases Gray Matter Volume in the Right Amygdala of Individuals with Low Back Pain: Confirmation of Previously Reported Magnetic Resonance Imaging Results.
Trial report in Pain medicine (Malden, Mass.), 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 23 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
23 citing papers in PubMed, 1 synthesis or guideline pooled it, 45 citations in OpenAlex.
- Pooled it
- Effects of morphine self-administration on brain structure and microglial phenotypic diversity in the absence of neuronal loss in male Wistar rats.Psychopharmacology · 2026Article
- Limbic System Microstructure in Neonates With Antenatal Opioid Exposure.JAMA network open · 2026Article
- Cross-sectional relationships between spinal cord gray matter volume and pain in individuals with fibromyalgia and opioid use.Scientific reports · 2025Article
- Neuroimaging of opioid effects in humans across conditions of acute administration, chronic pain therapy, and opioid use disorder.Trends in neurosciences · 2024Review
- Unveiling the link between chronic pain and misuse of opioids and cannabis.Journal of neural transmission (Vienna, Austria : 1996) · 2024Review
- Prescription Opioids and Brain Structure in Community-Dwelling Older Adults.Mayo Clinic proceedings · 2024Article
- The Emotion Regulation of Acupuncture in Chronic Low Back Pain: A Clinical Neuroimaging Protocol.Journal of pain research · 2024Article
- Research on the multidimensional brain remodeling mechanisms at the level of brain regions, circuits, and networks in patients with chronic lower back pain caused by lumbar disk herniation.Frontiers in neuroscience · 2024Article
- Pain, Opioid Analgesics, and Cognition: A Conceptual Framework in Older Adults.Pain medicine (Malden, Mass.) · 2023Article
- Is there hemispheric specialization in the chronic pain brain?Experimental neurology · 2022Review
- Does Gender Moderate the Relationship Between Chronic Pain and Substance Use Disorder? Insights From a National Canadian Population Survey.Frontiers in psychiatry · 2022Article
- Prenatal opioid exposure is associated with smaller brain volumes in multiple regions.Pediatric research · 2021Article
- Article
- Cognition and Pain: A Review.Frontiers in psychology · 2021Review
- Spinal Cord Resting State Activity in Individuals With Fibromyalgia Who Take Opioids.Frontiers in neurology · 2021Article
- Insular Cortical Thickness in Patients With Somatoform Pain Disorder: Are There Associations With Symptom Severity and Childhood Trauma?Frontiers in psychiatry · 2020Article
- Opioids affect the fetal brain: reframing the detoxification debate.American journal of obstetrics and gynecology · 2019Article
- Apparent Effects of Opioid Use on Neural Responses to Reward in Chronic Pain.Scientific reports · 2019Article
- Network Alterations in Comorbid Chronic Pain and Opioid Addiction: An Exploratory Approach.Frontiers in human neuroscience · 2019Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors at 3 institutions in 2 countries.
Funding
Abstract
objectiveProlonged exposure to opioids is known to produce neuroplastic changes in animals; however, few studies have investigated the effects of short-term prescription opioid use in humans. A previous study from our laboratory demonstrated a dosage-correlated volumetric decrease in the right amygdala of participants administered oral morphine daily for 1 month. The purpose of this current study was to replicate and extend the initial findings.
methodsTwenty-one participants with chronic low back pain were enrolled in this double-blind, placebo-controlled study. Participants were randomized to receive daily morphine (n = 11) or a matched placebo (n = 10) for 1 month. High-resolution anatomical images were acquired immediately before and after the treatment administration period. Morphological gray matter changes were investigated using tensor-based morphometry, and significant regions were subsequently tested for correlation with morphine dosage.
resultsDecreased gray matter volume was observed in several reward- and pain-related regions in the morphine group, including the bilateral amygdala, left inferior orbitofrontal cortex, and bilateral pre-supplementary motor areas. Morphine administration was also associated with significant gray matter increases in cingulate regions, including the mid cingulate, dorsal anterior cingulate, and ventral posterior cingulate.
conclusionsMany of the volumetric increases and decreases overlapped spatially with the previously reported changes. Individuals taking placebo for 1 month showed neither gray matter increases nor decreases. The results corroborate previous reports that rapid alterations occur in reward-related networks following short-term prescription opioid use.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.