Prescription opioid (PO) abuse is a growing public health concern worldwide as evidenced by an increasing number of opioid-related hospital admissions with a striking lack of research examining the neural basis underlying cognitive symptomatology. Drugs of abuse, through their impact on the dopaminergic system, are thought to disrupt the cognitive network regulating impulse control and incentive salience through inhibition of goal-oriented behaviour and drug-induced attentional biases. The objective of the present study is to examine neurocognitive processes in PO abusers (vs. healthy controls) by relying on the enhanced temporal resolution (1ms) of event-related potentials (ERPs) to track information processing abnormalities associated with cognitive control. In a naturalistic clinical study, 16 patients actively using prescription opioids and 16 healthy controls (matched for age, gender, educational level and smoking status) were assessed using a Go/NoGo and cue reactivity paradigm. Analysis revealed no significant differences in N2 or P3 amplitude, measures of inhibitory control, between groups after successful NoGo trials and no significant differences in ERN or Pe amplitude, measures of error processing, between groups after unsuccessful NoGo trials. Cue reactivity analysis of attention-related ERP components in patients demonstrated significantly (p<0.005) smaller P2 amplitudes, indexing the commencement of attentional processing, for drug pictures compared to neutral and affective pictures. Furthermore, stimulus type did not significantly modulate LPP amplitudes, indexing sustained attention, in patients however arousal ratings for drug pictures were positively correlated with LPP amplitudes in patients. These ERP results of altered cognitive control and incentive salience suggest the neural mechanisms underlying these cognitions are affected by chronic opioid abuse. Investigating the cognitive abnormalities experienced by PO abusers is an important factor in understanding the neural correlates of substance abuse and in predicting successful outcomes to ensure the best chance at long-term recovery for addicted individuals.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/37478 |
| Date | 16 April 2018 |
| Creators | Nelson, Renee |
| Contributors | Knott, Verner |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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