Neuropsychological functioning and chronic methadone use: A systematic review and meta-analysis

Abstract

Methodological 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.

Cognitive Functioning in Formerly Opioid-Dependent Adults after At Least 1 Year of Abstinence: A Naturalistic Study

“…The neurotoxic effects of opioids, cognitive deficits due to opioids, and possible remission of symptoms are a matter of debate [2,4,25,[43][44][45]. Previous studies in former opioid users showed a poorer performance than controls on some tasks, but most findings were without clinical relevance (e.g., [8]).…”

“…Schulte et al [1] concluded that sustained abstinence in people with substance use disorders generally results in (partial) neurocognitive recovery. Only limited data are available regarding cognitive functioning in opioid-dependent people so far (for recent reviews see [2][3][4][5]) and just a small amount of research has dealt with cognitive functioning in formerly opioid-dependent people [4,[6][7][8][9][10][11].…”

Does Cannabis Dependence Add on to the Neurocognitive Impairment Among Patients With Opioid Dependence? A Cross‐Sectional Comparative Study

“…The impairments of neurocognitive functions in patients with opioid dependence were consistent with the evidence in the literature. [1][2][3] Both the meta-analyses by Baldacchino and colleagues and Wollman et al done on patients using heroin (and other illicit opioids) and on patients undergoing methadone treatment revealed a global cognitive dysfunction in the domains of attention, cognitive impulsivity, decision making, psychomotor speed, and memory. The effect sizes estimated in these meta-analyses ranged from 0.11 (for attentional impairment) to 0.70 and 0.97 (for impairment in cognitive impulsivity and complex psychomotor function).…”

“…The most recent meta-analysis by Wollman and colleagues showed small to medium effect sizes for dysfunctions in attention, working memory, and executive function. 2 Another metaanalysis in individuals on methadone maintenance showed comparable cognitive impairment. 3 These reviews would unequivocally suggest an association of chronic opioid use (both illicit and used as treatment) and neurocognitive impairment.…”

“…Variable cognitive dysfunctions were observed in the domains of attention and executive function. The most recent meta‐analysis by Wollman and colleagues showed small to medium effect sizes for dysfunctions in attention, working memory, and executive function . Another meta‐analysis in individuals on methadone maintenance showed comparable cognitive impairment .…”