Cannabidiol on Reward- and Stress-related Neurocognitive Processes in Individuals With Opioid Use Disorder

The primary outcomes is cue-induced cravings (Opioid Craving Scale). This was measured with a single 10-point likert scale asking about cravings, where 0 represented lower levels of craving and 10 indicated higher levels of cravings. This was given at 3 different time points, pre-cue, post-neutral, and post-drug images. Cue-induced craving is the difference between drug cue and pre-cue scores.

Monetary Choice Questionnaire will be used to calculate impulse decision making. This is a 27-item self-administered questionnaire where participants choose between a smaller, immediate monetary reward and a larger, delayed monetary reward. A participants score is between one of the two endpoints (0.25 or 0.00016). If an individual is more likely to prefer the delayed versus immediate reward, their score is more likely to be closer to the 0.00016 endpoint. Please note the rate of delayed discounting is not the same for each question.

Iowa Gambling Task will be used to assess impulsive decision-making. The larger the number, the more "safer" options were chosen. This is measured by taking the total number of "risky" choices and subtracting it from the "less risky" choices. The lower the number, the more "high risky" options were chosen. If participants chose the less risky option, they received a positive point, if individuals picked the riskier choice, they received a negative point. Negative values indicate a participant chose more riskier decisions than less-risky, whereas positive values indicate participants chose the less riskier decision more often. The lowest score an individual could receive is -100 (very risk) to 100 (least risky).

Visual probe task will be used to assess attentional bias to drug-related cues. Opioid-related and neutral images will be used. Each trial will begin with a fixation point lasting 500ms. A pair of images then will appear on the left and right of the screen for either a short (200ms) or long (500ms) stimulus duration to assess automatic orientating and controlled attention processing, respectively. Image pairs will be replaced by a probe in the location of either the opioid-related or neutral image. The probe will remain until the participant responds to identify the probe orientation by pressing the response keys as quickly as possible. Attentional bias is calculated as the difference in reaction time (RT) between when the probe replaced the neutral compared with the opioid-related images (i.e. RTneutral - RTopioid). Therefore the more positive the number, the less attentional bias toward drug cue, and a negative number represents more attentional bias toward the drug cue.

Physiologic and subjective stress will be assessed. Stress-reactivity was measured by participants mirror tracing an image on a compute screen where a loud beeping noise would occur if a participant took too long or went outside the lines. It's measured in ms and the longer someone stayed on the task, the better ability they have to react stress.

For this outcome, participants received a salivary cortisol test prior to, immediately after, and 20 minutes after the cue-reactivity paradigm. Lower levels indicate lower levels of salivary cortisol in the sample.