AM 251 and other CB1r antagonists (e.g., rimonabant) have, in fact, yielded conflicting results in different animal models and tests of anxiety, ranging from anxiogenic and anxiolytic to null effects, with the former being the most common outcome [reviewed in 2–3]. AM 251, in particular, is reported to also act as a CB1r inverse agonist [23] and an antagonist
on adenosine type 1 receptors [24].