Cognitive and socio-cognitive functioning of chronic non-medical prescription opioid users

RationaleNon-medical prescription opioid use (NMPOU) has become a major public health issue in the USA and is also increasing in Europe. However, little is known about neuropsychological associations of NMPOUspecifically regarding social cognition, which is essential for social functioning and treatability of opioid dependence. Previous studies with heroin users and opioid-substituted patients reported deficits in various cognitive functions, but these results are likely confounded by comorbid physical and psychiatric diseases, overdose-associated hypoxia, and adulteration of street heroin. Therefore, the purpose of the present study was to investigate social and non-social cognition in a relatively pure NMPOU sample taking opioid analgesics or antitussives.MethodsWe assessed 23 individuals with NMPOU objectively confirmed by hair analyses and 29 opioid-naive, healthy controls, employing a comprehensive neuropsychological test battery.ResultsSignificant impairments were found between NMPOU individuals and controls regarding the cognitive domains of attention (p<.01, Hedge's g=.85), declarative memory (p<.05, g=.66), and global cognitive empathy (p<.01, g=0.99)the latter included problems with emotion recognition from faces, voices, and complex scenes. Opioid hair concentrations transformed to morphine equivalents were negatively correlated with global cognitive empathy (r=-0.52, p<.01), suggesting dose-dependent deficits.ConclusionIn contrast to stimulant users primarily displaying deficits in emotional empathy, opioid users showed relatively selective impairments in measures of cognitive empathy, with dose-dependent effects suggesting potential opioid-induced deficits and involvement of the opioid-system in processes of cognitive empathy. These results have important implications for future interventions of opioid dependence targeting social functioning and consequently enhancing therapy outcome and preventing relapse.