Key diagnostic criteria for illness anxiety disorder according to NICE guidelines are not explicitly detailed in the provided guideline excerpts.
The NICE guidelines referenced focus on social anxiety disorder, generalised anxiety disorder, panic disorder, and irritable bowel syndrome, but do not provide specific diagnostic criteria for illness anxiety disorder.
For accurate diagnosis of illness anxiety disorder, clinicians typically rely on clinical assessment of preoccupation with having or acquiring a serious illness, despite medical evaluation and reassurance, but this is not covered in the provided NICE guideline excerpts.