How to Observe Illness Through Smiles
Normal laughter reflects happiness. Medical researchers have found that many centenarians share a common trait: they love to laugh. China’s elderly longevity figures often appear cheerful and smiling. However, laughter may also conceal signs of underlying disease. In medicine, such laughter associated with illness is termed "pathological laughter."
Older adults suffering from diffuse cerebral arteriosclerosis may experience involuntary laughter due to ischemic degeneration of brain tissue leading to functional disorders. This is often accompanied by tremors in the upper limbs, unstable gait, and unclear speech.
Children with developmental disorders in the brain may display peculiar, foolish laughter—“foolish laughter”—often accompanied by obvious intellectual impairment. After excessive alcohol consumption, large amounts of alcohol enter the brain, disrupting the balance between excitation and inhibition, leading to wild laughter. This indicates acute alcohol poisoning.
Patients with tetanus exhibit tonic spasms of the masticatory muscles, causing the corners of the mouth to pull downward, the upper lip tightly pressed against the teeth, forming a “grimace” appearance. Patients with schizophrenia, due to abnormal brain function, experience hallucinations (auditory or visual), often muttering to themselves and laughing foolishly uncontrollably. This is known as forced laughter. Some experts believe such laughter often signals cellular degeneration or cerebral arteriosclerosis in the brain.
Therefore, in daily life, one should observe carefully. If such pathological laughter is noticed, seek medical attention promptly. Doctors can trace the root cause from the laughter itself, enabling correct diagnosis and treatment.