Do Adolescents and Adults Differ in Their Acute Subjective, Behavioural and Neural Responses to Cannabis, With and Without Cannabidiol?

Psychotomimetic effect

Time frame: Measured once, 2 hours after the start of drug administration, on each drug condition

Measured by total Psychotomimetic States Inventory (PSI) score

Verbal episodic memory

Time frame: Measured once, 2 hours after the start of drug administration, on each drug condition

Measured by delayed prose recall performance

Strength of subjective drug effect

Time frame: Measured 20 minutes after the start of drug administration, on each drug condition

Measured by self-reported 'feel drug effect', rated from 0 (not at all) to 10 (extremely)

Self-reported subjective effects

Time frame: Measured -30 minutes, 20 minutes, 30 minutes, 2 hours, and 2 hours & 40 minutes after the start of drug administration, on each drug condition

Feel drug effect, like drug effect, dislike drug effect, alert, want to have cannabis, happy, relaxed, anxious, paranoid, mentally impaired, stoned, dry mouth, unmotivated, intensified sensory perception, want to listen to music, want food, want to see friends, rated from 0 (not at all) to 10 (extremely)

Functional magnetic resonance imaging (fMRI) measured neural correlates

Time frame: Measured between 40 minutes and 1 hour & 20 minutes after the start of drug administration, on each drug condition

Reward anticipation and reward feedback, response inhibition, spatial working memory, and resting-state

Magnetic resonance spectroscopy

Time frame: Measured 1 hour & 30 minutes after the start of drug administration, on each drug condition

Measuring glutamate levels in the dorsal striatum

Positive and negative syndrome scale

Time frame: Measured 2 hours & 40 minutes after the start of drug administration, on each drug condition

Kay et al. (1987). Higher scores reflect stronger positive and negative symptoms.

Effort-related decision-making (i.e. amotivation)

Time frame: Measured 2 hours & 20 minutes after the start of drug administration, on each drug condition

Measured by the physical effort task ('apple-gathering' task) as described in Husain \& Roiser (2018)

Pleasure processing

Time frame: Measured 2 hours & 30 minutes after the start of drug administration, on each drug condition

Measured by subjective liking in response to chocolate, music and cartoons, rated from 0 (not at all) to 10 (extremely), similar to Lawn et al. (2015)

Visual attentional bias to cannabis and food stimuli

Time frame: Measured 2 hours & 10 minutes after the start of drug administration, on each drug condition

Measured by the visual dot-probe task, as described in Morgan et al. (2010)

Heart rate

Time frame: Measured -30 minutes, 20 minutes, 30 minutes, 2 hours, and 2 hours & 40 minutes after the start of drug administration, on each drug condition