time of data collection. In addition, participants were asked to refrain from using any psychoactive substances while participating in the study and notified that they would be subject to a random drug screen on the day of their scan. Immediately preceding neuroimaging data collection, every 10th male participant was asked to provide a urine sample, which was tested on a QuickScreen Pro Drug Screening test (Phamatech Inc, San Diego, CA) for the presence of amphetamine, methamphetamine, opiates, cocaine and tetrahydrocannabinol (THC). Due to the pharmacokinetics of THC,33 the presence of the chemical in urine was not deemed exclusionary unless the participant was acutely intoxicated. No participant was excluded for acute THC intoxication or tested positive for any other substance.
