Marsicano et al. (2002) showed that in mice, genetic deletion or pharmacological blockade of CB1R impaired fear extinction. Inactivation of CB1R by genetic deletion or by administration of a CB1R antagonist has also been studied with respect to its effect on unconditioned anxiety, with diverging outcomes seemingly dependent on dose, animal strain and testing conditions (Lafenêtre et al., 2007). The gene discussed is CNR1; the disease is Anxiety.