Three studies (two open, one double-blind) reported some effectiveness in treating panic disorder with verapamil, diltiazem, or nimodipine, while one open-label research reported failed treatment of anxiety and phobia with nifedipine in individuals with diverse anxiety disorders. There are no controlled studies evaluating the efficacy of these medications in treating other specific anxiety disorders such as social anxiety disorder or generalized anxiety disorder (GAD). The evidence supporting the use of calcium channel blockers for anxiety is limited to case reports and small studies; therefore, they should be used cautiously in patients who may be at risk for cardiovascular side effects due to their underlying condition.