A 32-year-old presents to the psychiatric mental health nurse practitioner following four brief episodes of intense anxiety occurring at home and work over the last two months. He reports the episodes "come out of the blue." During the episodes, he experiences dyspnea, heart palpitations, chest pain, tingling in his lips and fingers, and sweating. His symptoms are so severe he fears he is going to die. His primary care physician has ruled out a medical cause for the episodes. He has cancelled several work meetings out of fear that he might have another attack. The client meets DSM criteria for which listed diagnosis?

Choice A reason: The client meets the DSM-5 criteria for panic disorder, which requires recurrent, unexpected panic attacks ("out of the blue") followed by at least 1 month of persistent concern or worry about additional attacks. His avoidant behavior—cancelling meetings—is a direct result of the fear of the attack itself, confirming the diagnosis. Choice B reason: While the client is experiencing fear, he does not meet the criteria for a specific phobia. A phobia requires a marked fear or anxiety about a specific object or situation (e.g., spiders, heights). His anxiety is driven by the internal physiological sensations of a panic attack rather than an external phobic stimulus. Choice C reason: Agoraphobia involves marked fear about being in situations where escape might be difficult or help unavailable during a panic attack (e.g., public transport, open spaces). While he cancelled meetings, it was due to the fear of the attack's onset, not necessarily the inability to escape the room's physical layout. Choice D reason: Social anxiety disorder involves a persistent fear of being scrutinized or negatively evaluated by others in social situations. Although he is avoiding work meetings, the motivation is the physical fear of dying during a panic attack, not a primary fear of social embarrassment or judgment from his colleagues.