Study design and participants
familial psychosis
DISORDER, DISORDERS, RECRUITMENT
The experiment was registered on We conducted a randomised, double‐blind, placebo‐controlled, crossover experiment on the acute effects of cannabis in adolescents and adults. The experiment had a between‐subjects factor of age group (adolescent and adult) and a within‐subjects factor of drug (‘THC’, ‘THC + CBD’, ‘PLA’).This was a single‐centre study conducted at University College London and Invicro (Hammersmith Hospital, United Kingdom [UK]). We recruited healthy participants from the community in London, UK. The study received full ethical approval from UCL Ethics Committee (project code: 5929/005). This study was registered on We continued recruitment until we reached our target sample size of 48 completed participants, comprising 24 adolescents (50% female; 16–17 years old) and 24 adults (50% female; 26–29 years old). Participants who did not complete all sessions were replaced. Key inclusion criteria were self‐reported use of cannabis 0.5, 1, 2 or 3 days/week; healthy or overweight body mass index (BMI); and right‐handed. Key exclusion criteria were The Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM‐5) severe cannabis use disorder; currently receiving treatment for a mental health disorder; history of personal or familial psychosis; pregnant or breast‐feeding; use of any illicit drug (apart from cannabis) more than 2 days per month; nicotine dependence as defined by a Heaviness of Smoking score >1 [