Diagnosis

Although narcolepsy is a physical disorder, doctors are still very likely to misdiagnose patients as having psychologic problems. It often takes a year or longer for a patient with narcolepsy to receive a correct diagnosis. To determine specific sleep disorders, the doctor will take a medical and family history and should be told of any medications being taken. The symptoms of narcolepsy are sometimes undeniable if the patient reports all of the major symptoms:

Excessive daytime sleepiness with a tendency for frequent naps. (These frequent naps should occur every day for at least 6 months to serve as a diagnosis of narcolepsy.) Narcolepsy is usually diagnosed in adolescence and young adulthood when falling asleep suddenly in school brings the problem to attention.
Cataplexy (abrupt loss of muscle tone or weakness that causes a person to stop all motor activity).
Hypnagogic hallucinations (vivid visual or auditory phenomena) experienced at the onset of sleep.
Sleep paralysis (an inability to move on first awakening).

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Diagnosis based only on symptoms, however, is often problematic for various reasons:

Patients often seek medical help for single symptoms (sleep paralysis or hypnagogic hallucinations) that might be associated with other disorders, particularly epilepsy.
Symptoms are sometimes not dramatically apparent for years, even to the patient or a skilled observer. In one study, the average number of years between onset of symptoms and diagnosis was 14. Another study conducted in a sleep clinic reported that more than half of patients were diagnosed when they were over 40 and had not realized they had narcolepsy until they experienced a bout of cataplexy.

In some cases, the patient may need to consult a sleep specialist or go to an accredited sleep disorders center for accurate diagnosis of a sleep disorder. Patients should carefully investigate centers to make sure that they offer full sleep studies. Patients who visit a sleep center undergo an in-depth analysis, usually supervised by a multidisciplinary team of consultants who can provide both physical and psychiatric evaluations.