**Core Concept**
The diagnosis of organic mental disorders requires a comprehensive evaluation of the patient's cognitive, emotional, and behavioral functioning, as well as a thorough medical history and physical examination. Organic mental disorders, also known as neurocognitive disorders, are characterized by a decline in cognitive function due to a medical condition, such as Alzheimer's disease, stroke, or traumatic brain injury.

**Why the Correct Answer is Right**
The Mini-Mental State Examination (MMSE) is a widely used, standardized test that assesses various aspects of cognitive function, including orientation, attention, memory, language, and visuospatial skills. The MMSE is a useful tool for identifying patients with organic mental disorders and monitoring their progression or response to treatment. The test is relatively quick and easy to administer, making it a valuable resource for healthcare professionals in both clinical and research settings.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while a detailed medical history and physical examination are essential components of diagnosing organic mental disorders, they are not specific tests.

**Option B:** This option is incorrect because laboratory tests, such as blood chemistries or imaging studies, may be used to identify underlying medical conditions that contribute to organic mental disorders, but they are not diagnostic tests for the disorders themselves.

**Option C:** This option is incorrect because while neuropsychological tests can be useful in assessing cognitive function, they are not as widely used or standardized as the MMSE.

**Clinical Pearl / High-Yield Fact**
The MMSE is a useful tool for quickly assessing cognitive function, but it has limitations, particularly in patients with low educational levels or those who are unable to communicate effectively.

**Correct Answer: C. MMSE**