A 56-yrs-old man is brought to you by his wife because she has noted his personality change in the past 3 months. While the patient is being interviewed, he answers every question with the same three words. Which symptom best fits this patient’s behavior? NOT RELATED-PSYCHIATRY

**Core Concept**
The patient's behavior is an example of a formal thought disorder, specifically a symptom of schizophrenia characterized by a disorganized thinking pattern, where the individual's responses lack coherence and relevance to the question asked.

**Why the Correct Answer is Right**
The patient's repetition of the same three words in response to every question is indicative of a thought disorder, where the normal flow of thought is disrupted. This is often seen in schizophrenia, where the individual's thoughts may become disorganized, leading to a loss of logical coherence. In this case, the patient's responses are not relevant to the question asked, indicating a disconnection between the stimulus and the response.

**Why Each Wrong Option is Incorrect**
* **Option A:** There is no indication of a primary affective disorder, such as depression or bipolar disorder, which would typically present with a different set of symptoms, including changes in mood, appetite, or sleep patterns.
* **Option B:** The patient's behavior does not resemble a primary anxiety disorder, such as generalized anxiety disorder or panic disorder, which would typically present with symptoms of excessive worry, fear, or avoidance behaviors.
* **Option C:** The patient's responses are not indicative of a primary cognitive disorder, such as dementia or Alzheimer's disease, which would typically present with symptoms of memory loss, confusion, or difficulty with problem-solving.

**Clinical Pearl / High-Yield Fact**
In schizophrenia, thought disorders can manifest in various ways, including neologisms (made-up words), clang associations (using rhyming words), or echolalia (repeating words or phrases). These symptoms can be used to distinguish schizophrenia from other psychiatric disorders.

**Correct Answer:** C.

✓ Correct Answer: D. Perseveration