He and his colleagues have found that one patient in eight with symptoms of the syndrome actually has an underlying organic disorder.

Treatment is based on the underlying disorder and the symptom severity.

Otherwise, treatment relies on identifying and treating any underlying disorder.

There is no specific treatment, except treating the underlying disorder and providing adequate pain relief.

If there doesn't seem to be an underlying disorder, no further testing may be necessary.

Patients will also have evidence of their underlying disorder.

Even after treatment, the condition will recur unless the underlying disorder is treated.

But for perhaps 15 to 30 percent of those with chronic insomnia, no known underlying disorder can be found.

But an underlying disorder like sleep apnea may, in fact, be the problem keeping you up at night.

Babies born with different sized pupils may not have any underlying disorder.