Inclusion Criteria:  Adolescents: Aged 16-17 Adults: Aged 26-29 years Self-reported cannabis use between 0.5 and 3 days/week, averaged over the last 3 months Adults: Body mass index (BMI) between 18.5 and 29.9 Adolescents: BMI between 2nd percentile and 98th percentile Self-reported ability to consume approximately half a typical joint of cannabis by themselves within 20 minutes Willing to be cannulated and have four blood samples taken at every acute session Right-handed  Exclusion Criteria:  Females: Pregnant or breast-feeding Adults: Before the age of 18, had a period of 3 or more months when cannabis was used once per week or more frequently. Severe cannabis use disorder (DSM-5) Illicit drug use of any specific drug more than twice per month, averaged over the last 3 months Receiving treatment (pharmacological or psychological) for a mental health problem within the last month Lifetime psychosis Lifetime psychosis of any immediate family member Hypertension (systolic > 160 or diastolic > 100) Dependent on tobacco or vaping nicotine (> 1 on the Heaviness of Smoking Index) Currently taking a psychotropic medication that will likely affect dependent variables or interact with cannabis Any physical or mental health condition, any medication, or any treatment, that the study doctor considers to be an exclusion MRI contraindications Significant asthma or respiratory problems - severity judged clinically Self-reported moderate/severe acute unpleasant effects from cannabis which occur often or always Positive alcohol breathalyser reading at any acute session (rearrange session) Self-reported use of alcohol within 24 hours at any acute session (rearrange session) Self-reported use of illicit drugs (including cannabis) within 72 hours at any acute session (rearrange session) Positive saliva drug screen at any acute session (rearrange session)