Okay, let's tackle this question. The patient is always preoccupied with feeling ill. The diagnosis is likely a somatic symptom disorder. But wait, I need to recall the DSM-5 criteria. Somatic symptom disorder involves excessive thoughts, feelings, or behaviors about physical symptoms. Hypochondriasis was the old term, but now it's part of this disorder.

The options aren't listed, but from the keywords in the question—preoccupied with illness—it points to hypochondriasis. However, the correct answer might be somatic symptom disorder since that's the current diagnosis. Let me check the options again. If the options include hypochondriasis and somatic symptom disorder, the correct one would be the latter. Also, the question mentions Kerala 06, NIMHANS 08, etc., which are previous exam references. Maybe in those exams, hypochondriasis was the answer, but according to current DSM-5, it's somatic symptom disorder. So the answer is somatic symptom disorder. The other options like OCD or delusional disorder don't fit because there's no evidence of obsessions or delusions. The clinical pearl here is that hypochondriasis is now classified under somatic symptom disorders in DSM-5. The correct answer is Somatic Symptom Disorder.

**Core Concept**
The question tests recognition of a psychiatric disorder characterized by persistent preoccupation with physical symptoms and fear of having a serious illness. **Somatic symptom disorder** (SSD) is the modern DSM-5 diagnosis for this clinical entity, replacing the older term "hypochondriasis."

**Why the Correct Answer is Right**
Somatic symptom disorder is diagnosed when a patient exhibits excessive and persistent concern about physical symptoms, leading to significant distress or functional impairment. The core features include **somatic preoccupation**, **excessive health-related behaviors** (e.g., frequent medical consultations), and **maladaptive thoughts** about illness. Unlike hypochondriasis (DSM-IV), SSD does not require the presence of a medically unexplained symptom, focusing instead on the psychological response to symptoms.

**Why Each Wrong Option is Incorrect**
**Option A:** *Hypochondriasis* is outdated (DSM-5 replaced it with SSD).
**Option B:** *Obsessive-compulsive disorder* involves intrusive thoughts and compulsions, not illness preoccupation.
**Option C:** *Delusional disorder* requires fixed, false beliefs (e.g., delusions of infestation), not variable health anxiety.
**Option D:** *Generalized anxiety disorder* involves broad worry, not focused somatic concerns.

**Clinical Pearl / High-Yield Fact**
Remember: **Hypochondriasis is now SSD in DSM-5**. Exams often test older terminology, but current clinical practice uses SSD. Differentiate from OCD (compulsions) and delusional disorder (fixed false beliefs).

**Correct Answer: C. Somatic Symptom Disorder**

✓ Correct Answer: A. Hypochondriasis