**Core Concept**
Oniomania, also known as compulsive buying disorder, is a behavioral addiction characterized by a recurring inability to resist the urge to buy things, often resulting in significant distress or impairment in social, occupational, or other areas of life. It is classified under impulse control disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

**Why the Correct Answer is Right**
Oniomania is driven by a complex interplay of psychological, social, and environmental factors. Individuals with oniomania often experience feelings of anxiety, stress, or boredom, which they attempt to alleviate through shopping. This behavior is reinforced by the release of dopamine, a neurotransmitter associated with pleasure and reward, in response to purchasing and acquiring new items. The brain's reward system is hijacked, leading to compulsive behavior that is difficult to control.

**Why Each Wrong Option is Incorrect**
**Option A:** Hoarding disorder is a distinct condition characterized by the accumulation and failure to discard large quantities of possessions, leading to cluttered living spaces and significant distress. While hoarding can be related to oniomania, it is not the same disorder.

**Option B:** Kleptomania is a disorder characterized by the recurrent inability to resist the urge to steal objects that are not needed for personal use or for their monetary value. Oniomania involves compulsive buying, not stealing.

**Option C:** Pyromania is a disorder characterized by the deliberate and intentional setting of fires, often without apparent reason or reward. Oniomania involves compulsive buying, not fire-setting.

**Clinical Pearl / High-Yield Fact**
Oniomania is often comorbid with other mental health conditions, such as depression, anxiety disorders, and substance use disorders. Recognizing these comorbidities is essential for effective treatment and management.

**Correct Answer:** D.