A 45-year-old man shows excessive health-related anxiety and checks his pulse frequently. What diagnosis fits this description?

The description of excessive health-related anxiety and frequent checking of his pulse aligns closely with the diagnosis of illness anxiety disorder. This disorder is characterized by a preoccupation with having or acquiring a serious illness, often leading individuals to misinterpret bodily sensations or minor physical symptoms as signs of serious medical issues. The behavior of constantly checking his pulse is indicative of the need for reassurance and reflects an excessive concern about health.

While generalized anxiety disorder involves broader anxiety across various domains and panic disorder includes recurrent episodes of intense fear that may involve physical symptoms, neither captures the specific focus on health and bodily sensations that is central to illness anxiety disorder. Similarly, somatic symptom disorder involves the presence of somatic symptoms that cause significant distress or impairment, but it is not solely focused on the fear of having a serious illness. Thus, the characteristics presented in the scenario strongly support the diagnosis of illness anxiety disorder.