**Core Concept**
Trichotillomania is a psychiatric disorder characterized by a recurring, irresistible urge to pull out one's own hair, resulting in noticeable hair loss. This behavior is often associated with anxiety, stress, or other emotional states. The term "trichotillomania" comes from the Greek words "tricho" meaning hair and "tillo" meaning to pull.

**Why the Correct Answer is Right**
The correct answer is C. Compulsive hair pulling because it accurately describes the core symptom of trichotillomania. Individuals with this disorder often exhibit a strong urge to pull out their hair, which can be triggered by various factors such as stress, boredom, or anxiety. This behavior can lead to noticeable hair loss, social embarrassment, and significant distress. The underlying pathophysiology is thought to involve abnormalities in brain regions involved in impulse control, such as the orbitofrontal cortex and anterior cingulate cortex.

**Why Each Wrong Option is Incorrect**
**Option A:** Irresistible desire to set fire is a characteristic of pyromania, a different psychiatric disorder. While both conditions involve compulsive behaviors, they target different aspects of behavior (hair pulling vs. fire setting).
**Option B:** Irresistible desire to steal things is a characteristic of kleptomania, another distinct psychiatric disorder. Kleptomania involves compulsive stealing, often without regard for material gain or financial need.

**Clinical Pearl / High-Yield Fact**
Trichotillomania often co-occurs with other psychiatric disorders, such as anxiety disorders, depression, and obsessive-compulsive disorder. Recognizing this comorbidity is essential for effective treatment planning, which may involve a combination of psychotherapy, behavioral modification, and pharmacological interventions.

✓ Correct Answer: C. Compulsive hair pulling