Narcolepsy is a neurological disorder characterized by excessive sleepiness. It's caused by destruction of a group of neurons in a part of our brain called the hypothalamus. The hypothalamus is important in regulating our hormones, many of which control basic functions like sleep and hunger. Because of the location in the brain, reports have linked narcolepsy to elevated weight and even type 2 diabetes. It's been theorized that patients with narcolepsy have reduced sensitivity to insulin, much like type 2 diabetics.
This study was done to assess both blood sugar and fat metabolism in a small group of narcoleptics and compared them to a matched control group that did not have narcolepsy. They used a sophisticated test to measure both fat and blood sugar metabolism, something that had not been done before in older studies of patients with narcolepsy. The results were interesting in that the researchers found that narcoleptics had increased insulin sensitivity in the periphery - the opposite of what they expected. Liver cell insulin sensitivity and pancreatic function were the same as matched controls. Fat metabolism tended to be lower in patients with narcolepsy, which may explain in part why narcolepsy is linked with being overweight.
The researchers also treated the narcoleptic patients with sodium oxybate, a medicine that improves some of the narcolepsy symptoms. It's taken at night, and improves the patients' sleep quality, although it's not a sleep aid. Interestingly, the sodium oxybate increased fat metabolism, and the narcoleptic patients lost an average of 5.2 kg (11.5 pounds) in the three months of the study. The exact mechanism of the weight loss is not known.
The bottom line is that the results of this study do not support an increased risk of type 2 diabetes in narcoleptics. Also, patients with narcolepsy that are treated with sodium oxybate may lose weight, although the exact mechanism is unclear.