| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5043528 | Neuroscience & Biobehavioral Reviews | 2017 | 16 Pages |
â¢A broad range of domains of neuropsychological performance are significantly impaired in studies which have compared methadone populations with the healthy controls. However low power, poor quality and heterogenous populations limit the interpretation of these results.â¢Short term (less than 1âyear) abstinent groups, when compared with methadone groups, still exhibited cognitive impairments but results are inconclusive.â¢It is still not clear what the role of global sedative effects of opioids such as methadone have on cognitive impairment.â¢Only higher quality longitudinal studies using ecologically valid cognitive tests, in well-defined population groups can address this question.â¢Methadone populations present with a broad range of neuropsychological impairment when compared with healthy controls.
IntroductionThere is a presumption that neurocognition is commonly impaired in chronic methadone exposed individuals (CM) when compared with healthy controls (HP). Additionally, it remains unclear if short term (<1 year) abstinence (AP) is associated with an altered cognitive profile when compared with CM.MethodA random effect model approach was used on data assembled into the Comprehensive Meta-Analysis programme. Cohen's d effect sizes and a significance levels of p < 0.01 were calculated for each domain.ResultsData from a total cohort of 1063 CM, 412 AP and 879 HP participants, from 23 independent studies indicate global impairments in neurocognitive function in CM relative to HP participants. The smaller body of evidence comparing CM to AP participants is inconclusive.ConclusionMethodological issues such as small sample sizes, heterogeneity and poor quality limited the interpretation of the results and does not address whether the observed impairments reflect co-morbid functioning, methadone-related sedation and/or other factors. Only higher quality longitudinal studies will permit confident interpretation of the results observed in this meta-analysis.
