Participants
allergies
COLOR BLINDNESS, RECRUITMENT, ALLERGIES
Recruitment and data collection took place from October 2019 to March 2020 at the University Hospital Essen in Germany. Participants were recruited via flyers and posters at regional universities and the University Hospital Essen, via an in-house participant database and via social media. Those between 18 and 60 years of age were eligible to take part. Exclusion criteria comprised severe chronic or acute clinical conditions, regular substance use of cannabinoids, cocaine, or amphetamines in the last 4 weeks, color blindness, known allergies or intolerance against the ingredients of the placebo medication, pregnancy or breastfeeding, alcohol consumption on the testing days or the day before, or participation in other (medication-related) studies in the three weeks of testing. All participants underwent an initial phone interview and gave written, informed consent prior to participation. All participants received 50 € after study completion, plus the bonus gained in the Instrumental Learning Task (means and standard deviations are always reported as We collected data from 100 participants. Data of those participants who had only completed the Baseline assessment were discarded (