A 35 year old has a firm unshakable belief that his wife is cheating on him. He never allows her to go out of home alone and locks his house, while going out. In spite of all this, he is persistently suspicious that his wife has an affair. The probable diagnosis is:
**Core Concept**
The question is testing the understanding of a classic psychiatric condition characterized by a persistent, unfounded, and intrusive thought that causes significant distress and impairment in social and occupational functioning. This condition is often associated with a sense of certainty and resistance to evidence that contradicts the thought.
**Why the Correct Answer is Right**
The correct answer is **Delusional Disorder**. In this condition, the patient holds a fixed, false belief that is not amenable to change in light of conflicting evidence. The patient's belief that his wife is cheating on him is a classic example of a delusion of infidelity, which is a common type of delusion in Delusional Disorder. Despite the lack of evidence and the wife's reassurances, the patient remains convinced of his wife's infidelity.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Hypochondriasis is a condition where a person has excessive worry about having a serious illness, but it does not involve delusions of infidelity.
**Option B:** This option is incorrect because Depressive Disorder can involve delusions, but they are typically mood-congruent (e.g., delusions of guilt or worthlessness) and not typically involve delusions of infidelity.
**Option C:** This option is incorrect because Schizophrenia can involve delusions, but they are typically more complex and disorganized than the fixed, false belief of infidelity seen in Delusional Disorder.
**Clinical Pearl / High-Yield Fact**
Delusional Disorder is a chronic condition that can be challenging to treat, but cognitive-behavioral therapy and antipsychotic medications can be effective in managing symptoms. It is essential to address the underlying psychological and social factors contributing to the development of the delusion.
**Correct Answer:** C.