Morgellons disease - a creepy illness that leaves patients with painful lesions, gives them a feeling that bugs are crawling all over their body, and has them seeing colorful, threadlike fibers poking through their skin - isn't infectious and probably isn't caused by anything in the environment, according to the first government study of the condition.

Rather, Morgellons is likely to be a mental illness and should probably be treated with the same drug and psychiatric care that works for people who suffer delusions, researchers with the U.S. Centers for Disease Control and Prevention said Wednesday.

"There were some possibilities of what could be causing this, and we've taken a couple of the big ones off the table. That's a really big step forward," said Dr. Mark Eberhard, director of the CDC's Division of Parasitic Diseases and Malaria and a lead investigator in the study.

Seeking acknowledgement

The study focused on patients in the Bay Area, where a cluster of Morgellons cases have been reported over the past several years. Patients all complained of the same strange, often horrifying symptoms, and they became increasingly angry and frustrated that physicians weren't taking their condition seriously.

Just getting the research done was a major coup for Morgellons sufferers, who had been clamoring for a serious scientific study of their illness for years. But by ruling out infectious and environmental causes of the disease and suggesting it's a delusional condition, the CDC report was disappointing, patients said Wednesday.

Most of them aren't ready to accept that the mysterious illness that plagues them is all in their head.

"We just want to be acknowledged. This is not a delusion," said Cindy Casey, 49, who worked as a nurse in a Bay Area intensive care unit for 16 years before she went on disability from Morgellons. She now lives in Texas, where she runs a foundation for Morgellons research.

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"We would really love to understand the etiology and be able to hope for some kind of treatment," Casey said. "A cure is really too much to ask for at this point, but to be able to manage the symptoms would be good."

Casey said she suffers from lesions all over her body and a "popping and tingling" sensation, primarily in her legs. She itches all over, so badly that it's painful and she has trouble sleeping, she said.

The symptoms can be so maddening, she said, that she has no doubt that many Morgellons patients come across as "crazy" to doctors - and it's not surprising that she and others are labeled as delusional, she admits.

'We don't really understand'

Dr. Raphael Stricker, a Lyme disease specialist who treats about 60 people in the Bay Area whom he says suffer from Morgellons, agreed that his patients often seem delusional. "If you had these fibers coming out of your skin, wouldn't you go a little nuts?" he said.

But he's convinced that Morgellons is not a mental illness and has done his own research to try to find a cause, or at least an explanation for the strange filaments he's seen growing out of and under patients' skin.

"I want to commend the CDC for doing this study and trying to get a handle on this disease, which has baffled many people and is a big problem," Stricker said. "But the only thing it really tells us clearly is that we need to do more work, because we don't really understand this disease."

The CDC study focused on members of Kaiser Permanente Northern California, using patient records to find people who suffered from symptoms commonly associated with Morgellons. They found 115 such patients, most of them middle-age white women. That worked out to about 4 cases per 100,000 Kaiser members, making the condition very rare, Eberhard said.

While there was no doubt that the patients were all sick, the cause of their illness was unclear, researchers found. More than two-thirds of patients reported chronic fatigue, and about 60 percent had cognitive problems, often related to memory or their ability to concentrate.

Fibers blamed on clothing

All of the patients had complained at least once of some kind of threadlike filament growing out of their skin. Most patients identified the filaments as fibers, but some referred to them as worms, "fuzz balls" or larvae. The CDC researchers examined filaments taken from 12 patients and found that they were most likely fibers that came from clothing and had stuck to the skin.

"Clearly these people have something that's very impactful on their health," Eberhard said. "But a number of those problems can be treated. We really think there's the potential to significantly help a fair number of these folks."