CNR1 and Anxiety: However, protracted administration of a CB1 antagonist, which produces a 'depressive’-like phenotype, actually decreased monoamine and BDNF levels[74], indicating that while acute effects may suggest an antidepressant response, clearly sustained inactivation of CB1 receptor signaling produces adverse changes in emotional behavior, such as increased anxiety, and evokes a biochemical signature similar to that seen following chronic stress.