Ambien illustrates mysteries of the brain

In 2006, when John Whyte first started studying the remarkable effect that the sleep medicine Ambien can have on people with severe brain damage, he hoped the drug might be a miracle treatment.

Six years later, Ambien's ability to rouse some people from oblivion remains tantalizingly mysterious. But Whyte, director of the Moss Rehabilitation Research Institute in Elkins Park, no longer sees the drug as a potentially dramatic improvement in care.

Now he sees something far more complex.

Ambien, he said, reveals how little we understand about consciousness.

"What this drug shows is that not everybody who appears to be permanently unconscious with no hope of regaining consciousness is," Whyte said.

That knowledge can make family decisions about when to let go even more agonizing. It provides an argument for giving more aggressive medical treatment to people in vegetative or minimally conscious states and for waiting longer before giving up.

In addition, a drug that helps doctors separate people whose brains are still capable of working from those with more devastating damage could help scientists identify the best candidates for clinical trials. If people can be awakened, however briefly, by a medicine, Whyte said, "it implies they have the machinery for consciousness." It is far more cost-effective, he said, to study new treatments among those most likely to benefit.

Ambien, or its generic form, zolpidem, is widely used to help people fall asleep, but it is also famed for its strange side effects. Not only do some users walk in their sleep, but they drive, prepare and eat food, make phone calls, and have sex. They usually don't remember it.

After anecdotal reports that Ambien could "wake" some people from unconsciousness, Whyte conducted a small trial of the drug in people in vegetative and minimally conscious states (one or two steps above coma) and is now completing a larger study with 75 patients.

Noticeable improvement

Because these patients had severe brain tissue damage, no one who took the drug suddenly became normal. "I haven't had anyone who started a conversation after the drug," Whyte said. But about 7 percent of the patients improved noticeably after they took Ambien - someone was able to follow an object with his eyes, or follow a command.

"They weren't dramatic results, but they were dramatic for those patients," Whyte said.