Neurocognitive Functions in Opioid Dependence: Comparisons Between Opioid Categories

We examined the differences in neurocognitive functions in individuals dependent on heroin (n = 120), pharmaceutical (n = 52), and natural opioids (n = 66) and compared with healthy controls (HC, n = 94). We estimated independent effects of the opioid groups on cognitive tests, adjusted for effect modifiers. Pharmaceutical opioid dependent group performed worse than HC in Wisconsin Card Sorting Test in conceptual level response and trials to complete first category. Pharmaceutical and heroin groups had higher error scores than HC in verbal and visual N-Back Tests (NBTs). There was no significant difference between pharmaceutical and heroin groups, but both had higher error scores than the natural opioid users in NBTs. Time to complete Trail Making- A test was higher in pharmaceutical than in natural opioid group. The natural opioid group required more trials than HC to complete the first category. Pharmaceutical opioid group had worst cognitive impairment. Cognitive functions are relatively spared in natural opioid-dependent group.