Neurocognitive impairments and brain abnormalities resulting from opioid-related overdoses: A systematic review

• Published in: Drug and alcohol dependence 2021-09, Vol.226, p.108838-108838, Article 108838
• Main Authors: Winstanley, Erin L., Mahoney, James J., Castillo, Felipe, Comer, Sandra D.
• Format: Article
• Language: English
• Subjects: Abnormalities; Adolescent; Adult; Analgesics, Opioid - adverse effects; Attrition; Bias; Brain; Brain abnormalities; Brain injuries; Brain injury; Brain research; Case reports; Cognition; Cohort analysis; Confounding factors; Drug overdose; Drug Overdose - epidemiology; Head injuries; Humans; Hypoxia; Injuries; Injury prevention; Magnetic resonance imaging; Measuring techniques; Medical treatment; Narcotics; Neurocognition; Neurocognitive impairments; Opiate Overdose; Opioid-related overdose; Opioids; Overdose; Overdoses; Psychology; Reviews; Risk management; Substance use; Substance use disorder; Substance-Related Disorders; Systematic review; Toxicology; Traumatic brain injury
• ISSN: 0376-8716; 1879-0046
• DOI: 10.1016/j.drugalcdep.2021.108838

•Brain injuries and cognitive deficits have been reported after opioid overdose (OD).•Opioid OD causes respiratory depression and potentially cerebral hypoxia.•Studies over 50 years, across 21 countries, reported OD-related brain injuries.•Prevalence and consequences of OD-related brain injuries is unknown.•Rigorous methodological within-subject studies are needed to establish causality. Non-fatal opioid-related overdoses have increased significantly over the past two decades and there have been increasing reports of brain injuries and/or neurocognitive impairments following overdose events. Limited preclinical research suggests that opioid overdoses may cause brain injury; however, little is known about such injuries in humans. The purpose this systematic review is to summarize existing studies on neurocognitive impairments and/or brain abnormalities associated with an opioid-related overdose in humans. PubMed, Web of Science, Ovid MEDLINE and PsyINFO were searched, without year restrictions, and identified 3099 articles. An additional 24 articles were identified by reviewing references. Articles were included if they were published in English, reported study findings in humans, included individuals 18 years of age or older, and reported an objective measure of neurocognitive impairments and/or brain abnormalities resulting from an opioid-related overdose. Six domains of bias (selection, performance, attrition, detection (two dimensions) and reporting were evaluated and themes were summarized. Seventy-nine journal articles, published between 1973–2020, were included in the review. More than half of the articles were case reports (n = 44) and there were 11 cohort studies, 18 case series, and 6 case-control studies. All of the studies were categorized as at-risk of bias, few controlled for confounding factors, and methodological differences made direct comparisons difficult. Less than half of the studies reported toxicology results confirming an opioid-related overdose; 64.6 % reported brain MRI results and 27.8 % reported results of neuropsychological testing. Only two studies had within subject comparative data to document changes in the brain possibly associated with an overdose. Despite these limitations, existing publications suggest that brain injuries and neurocognitive impairments are associated with opioid overdose. Additional research is needed to establish the incidence of overdose-related brain injuries and the potential impact on functioning, a