Eating Disorders often Accompany Narcolepsy with Catalepsy

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Last Updated: 2008-03-27 14:40:27 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Many patients with narcolepsy with cataplexy also experience a number of symptoms of eating disorders, according to findings from a Dutch study reported in the journal Sleep.

People with narcolepsy suffer from episodes in which they suddenly fall asleep. These "sleep attacks" occur even if they have had enough sleep the night before. Cataplexy is the sudden loss of control over voluntary muscles -- patients will feel weak and collapse - sometimes injuring themselves. These episodes are triggered by strong emotions such as anger, fear or surprise.

Aside from the main features of excessive daytime sleepiness and cataplexy, one of the more prominent symptoms of narcolepsy is an increase in body weight, Dr. Hal A. Droogleever Fortuyn, of Radboud University Nijmegen Medical Center, and colleagues point out. There have also been some reports of symptoms of eating disorders in these patients, they add.

To look into this, the team compared symptoms of eating disorders in 60 patients with narcolepsy with 120 subjects matched for age and sex who served as a control group.

The researchers found that 23.3 percent of the patients but none of the controls met the criteria for an eating disorder. Most of the patients were classified as having an eating disorder - "not otherwise specified," with an incomplete form of binge-eating disorder.

Approximately half of the patients had a persistent craving for food, experienced an earlier episode of overeating, and reported binge eating, while 25 percent of the patients reported binge eating at least twice a week.

In a separate study, the investigators examined whether an increased body mass index could be responsible for eating disorder symptoms. To that end, they compared 32 narcolepsy patients with 32 controls of the same height and weight.

The researchers found that the narcolepsy patients had a significantly increased frequency of overeating episodes, binge eating, and a persistent craving for food compared with the control group.

Medication use did not influence the prevalence of symptoms and diagnoses of eating disorders. Patients who used antidepressants had a slight trend toward more craving and reported more interference in activities due to eating problems.

Fortuyn and colleagues note that most cases of narcolepsy are caused by a deficiency of hypocretin neurotransmission, and they propose that eating disorder symptoms could be a direct consequence of hypocretin deficiency.

The hypocretin system has connections to cells in the region of the brain that produces a "precursor" of melanocortin, they note. "Hypocretin deficiency may directly influence melanocortin signaling, which in turn may cause eating disorders."

SOURCE: Sleep, March 1, 2008.

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