This chapter focuses on a biological perspective on panic disorder by summarizing several theories of anxiety, fear, and panic disorder that are rooted in neuro-anatomy and physiology. Most patients with panic disorder who are successfully treated with either imipramine or alprazolam and then retested do not experience the attacks. Dr. Patel was struck by the great intensity of Latisha's panic attacks, leading her to tentatively discount obsessive-compulsive anxiety or phobic disorders. Dr. Patel evaluated Latisha for major depression, which occurs in about half of persons who have panic disorder, and has important implications regarding treatment. Treatment began with Dr. Patel educating Latisha about panic disorder. The educational process included information about treatment alternatives, especially medications and cognitive-behavioral techniques. Medication was most likely to act physiologically in reducing Latisha's tendency to generate the dramatic arousal she experiences as part of a panic attack.