{
  "abstract": "Background: Despite the ongoing opioid-related public health emergency in North America, the influences of non-fatal opioid overdose on brain structure remain unclear, largely due to a paucity of pre-overdose brain images. Hippocampal atrophy, potentially with corollary cognitive deficits, associated with hypoxic insult is a possible consequence of non-fatal opioid overdose.\n\nResearch objectives: Investigate overdose-associated changes in hippocampal volume.\n\nMethods: Linear mixed effect modelling indexed hippocampal volume changes captured in repeat brain MRI from before and after self-reported opioid overdose in 22 individuals. Data from 66 propensity-matched non-overdosing participants are the reference for unrelated changes (mean 1.7 years between scans). Participants were from a naturalistic cohort study of health of vulnerably housed people in Vancouver, Canada (N = 515, 2008–2023). Follow-up paired tests of cognitive data from assessments completed close to the time of MRIs explore possible overdose-associated changes in memory and processing speed (operationalized as composite scores respectively derived from the Hopkins Verbal Learning and Stroop tests).\n\nResults: Participants who overdosed between MRIs had more hippocampal volume loss compared to reference participants (97 mm3 versus 25 mm3 mean loss of bilateral hippocampal volume, respectively; χ² group-time = 4.8, p = .029, B = -47.1; χ² time = 1.6, p = .211, B = -13.6). Irrespective of overdose, memory performance was unchanged around this time (overdose between assessments: V= 89.00, p = .825, rrb = -.06; reference group: V=898.50, p =.738, rrb = -.05). There was a trend towards decreasing processing speed for those who overdosed (t(18)=2.11, p =.049, Hedge’s g =0.46; means before and after overdose: 0.08 and -0.30), without changes in the reference group (t(61)=-1.10, p=.275, g =-0.14).\n\nConclusions: Loss of hippocampal volume and potentially processing speed may be associated with non-fatal opioid overdose.\n\nKey messages: • In this retrospective matched cohort analysis, 22 individuals with self-reported opioid overdose between brain MRIs, matched to 66 similar participants, had greater decreases in hippocampal volume.\n\n• Participants showed a trend towards decreased processing speed, without changes in memory, between cognitive assessments before and after self-reported opioid overdose.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "abstract",
  "arxiv": null,
  "author_total": 10,
  "authors": [
    {
      "name": "S A Saint"
    },
    {
      "name": "L N Farah"
    },
    {
      "name": "B K Nelson"
    },
    {
      "name": "A E Thornton"
    },
    {
      "name": "D J Lang"
    },
    {
      "name": "K M Gicas"
    },
    {
      "name": "A T Vertinsky"
    },
    {
      "name": "W Su"
    },
    {
      "name": "W G Honer"
    },
    {
      "name": "W J Panenka"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/90qztxjfzke03.bib",
  "cited_by": 0,
  "doi": "10.1093/eurpub/ckag169.1097",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13698450/",
  "id": "90qztxjfzke03",
  "issns": [
    "1101-1262",
    "1464-360X"
  ],
  "landing_url": "https://doi.org/10.1093/eurpub/ckag169.1097",
  "language": "en",
  "licence": "CC-BY-NC-4.0",
  "licence_label": "CC BY-NC 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "6. Poster Displays"
    ],
    [
      "heading",
      "AcademicSubjects/MED00860"
    ],
    [
      "heading",
      "AcademicSubjects/SOC01210"
    ],
    [
      "heading",
      "AcademicSubjects/SOC02610"
    ],
    [
      "heading",
      "DB. Chronic diseases, multimorbidity and non-communicable diseases"
    ],
    [
      "openalex",
      "2739|Opioid Use Disorder Treatment"
    ]
  ],
  "openalex": "W7223674262",
  "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13698450/pdf/?tool=EBI",
  "pmcid": "PMC13698450",
  "pmid": null,
  "published": "2026-10-01",
  "publisher": "Oxford University Press",
  "ris": "https://research.draconitic.com/paper/90qztxjfzke03.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:20Z",
      "native_id": "PMC13698450",
      "source": "pmc",
      "url": "https://doi.org/10.1093/eurpub/ckag169.1097"
    },
    {
      "first_seen": "2026-10-30T12:21:44Z",
      "native_id": "PMC:PMC13698450",
      "source": "europepmc",
      "url": "https://europepmc.org/article/PMC/PMC13698450"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2739|Opioid Use Disorder Treatment",
      "subfield": "epidemiology-public-health"
    }
  ],
  "title": "Hippocampal and cognitive changes following non-fatal opioid overdose",
  "title_text": "Hippocampal and cognitive changes following non-fatal opioid overdose",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:35:19Z",
  "url": "https://research.draconitic.com/paper/90qztxjfzke03",
  "venue": "The European Journal of Public Health",
  "versions": []
}