Cannabis is one of the most widely used drugs in the world, with historical records dating use in Eastern cultures back millennia [1]. Cannabis and its derivatives have profound effects on a wide variety of behavioral and neural functions, ranging from feeding and metabolism to pain and cognition [2]. However, epidemiological studies have indicated that the most common self-reported reason for using cannabis is rooted in its ability to reduce feelings of stress, tension, and anxiety [3]. Significant numbers of people may be self-medicating with cannabis in an attempt to reduce excessive anxiety [4,5] (even though cannabis use can also cause paranoia and heightened anxiety in certain situations and predisposed individuals, depending on the dose [6]). Furthermore, studies in controlled clinical settings confirm that administration of synthetic variants of delta-9-tetrahydrocannabinol (THC), the psychoactive constituent of cannabis, can reduce anxiety in patients with anxiety disorders [7,8]. Finally, the anxiety-reducing properties of THC extend to preclinical rodent assays and models [9], demonstrating that the anxiolytic properties of cannabinoids are well conserved across species.
