Intensity
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Subjective intensity of effects was assessed acutely via experience sampling from 8 min prior to 52 min after the start of the bolus injection. For this, audio prompts were played through headphones, and participants were instructed to verbally give subjective ratings of the intensity of the experience (from 0 = ‘no effects’ to 10 = ‘most intense imaginable’). These were collected at −8, −6, −4, −2, 0, 1, 2, 3, 4, and every 2 min thereafter, with minute 0 being the start of the bolus injection.