A 28-year-old man named David presents to a mental health clinic with complaints of sudden episodes of intense fear, described as 'panic attacks'. He mentions feeling a racing heart, shortness of breath, and a strong fear of losing control during these episodes. Notably, he avoids situations that he associates with previous panic attacks. David's history reveals that he has experienced these episodes intermittently over the past 6 months.

Which of the following diagnoses is most consistent with David's symptoms and behavioral history?