The most important thing: Hirvonen 2012 PET study: Daily cannabis users have 15-20% fewer CB1 receptors in the cortex. This is the neurobiological cause of tolerance. After 4 weeks of abstinence: measurable recovery of receptor density. At a glance: PET study: daily users have 15-20% fewer CB1 receptors in the cortex (Hirvonen 2012) After 4 […]