A 40-year-old man reports episodes in which he unexpectedly feels a surge of intense fear that peaks within minutes. During this time he feels dizzy, has shortness of breath, heart palpitations, and feels like he is "going crazy." These episodes seem to come "out of the blue" with no trigger that he can identify. He has had them when he has been napping on the weekend or during a break at work. He is starting to think he is really "going crazy," because he has no medical conditions, doesn't drink or smoke, and says there are no new stressors in his life that could be causing this. What is the most likely diagnosis?

Choice A reason: Panic attacks are discrete episodes of intense fear, but the diagnosis requires recurrent unexpected attacks and concern about future attacks. Choice B reason: Panic disorder is correct. It involves recurrent, unexpected panic attacks and persistent worry about having additional attacks, which aligns with the patient’s experience. Choice C reason: Generalized anxiety disorder involves chronic, pervasive worry, not sudden, discrete panic episodes without identifiable triggers. Choice D reason: Substance or medication-induced panic disorder is ruled out by the patient’s lack of substance use and medications, making this diagnosis unlikely.