The study, by the U.S. Centers for Diseases Control, rules out infectious diseases and environmental exposures as a possible cause of the rarely reported condition.
Published Wednesday in the Public Library of Science journal PLoS One, the study notes that many of the people tested had other medical ailments, including depression and other neuropsychiatric conditions. It suggested treatment for these other conditions could help sufferers with the symptoms they associate with Morgellons.
Reading between the sensitively worded lines, the study appears to be saying Morgellons — which some in the medical community describe as delusional parasitosis — is in the sufferers' minds. But the CDC, which for years received pleading calls from sufferers seeking help, was not willing to put it in such bald terms.
"Where we're on the highest ground is to say we found no infectious cause and we don't think there's an environmental link. And the fibres are inanimate objects that are not playing a role in this," said Mark Eberhard, a parasitologist who was the senior author on the study.
Eberhard, who is director of the division of parasitic diseases and malaria in the CDC's Center for Global Health, said the CDC plans no further studies on Morgellons at this time. The just-completed study cost the Atlanta-based agency US$580,000.
The fibres to which Eberhard referred are a key and consistent feature of Morgellons, whose sufferers complain of excessively itchy skin that feels like there is something moving under it or embedded in it.
Many have reported finding fibres working their way through their skin and have sent them off to be tested. Doctors who see these patients talk about recognizing them because they come in armed with plastic baggies or matchboxes containing fibres they say have extruded from their skin.
In the CDC's study, scientific analysis was done on fibres collected from the lesions of several people in the presence of the researchers. But the U.S. Armed Forces Institute of Pathology determined the fibres were just that — tiny threads, such as those that might come from clothing, that had stuck to abscesses and scabs that were self-inflicted by excessive scratching.
"These fibres are inanimate. They're cotton, they're nylon. They're not part of the problem either," Eberhard said.
In early 2008 the CDC announced it would study Morgellons, trying to determine if it is an actual condition or disease or merely a symptom of mental health issues in the sufferers.
It used health insurance data from Northern California to identify 115 people who complained of symptoms that resembled the condition, and studied them extensively.
The people — many of whom dropped out along the way — filled in detailed surveys about themselves and their daily lives and exposures. They underwent psychological testing. Some had skin biopsies designed to see if there were parasites in their lesions. They were given in-depth physical examinations, which included blood and urine testing, and analysis of hair for evidence of drug taking.
Many had a variety of ailments and reported having a poor quality of life. Nearly 60 per cent had at least one cognitive problem. "The common term that they used was brain fog," said Eberhard. "Trouble concentrating. Trouble with remembering things. Feeling like they're in a fog."
The researchers found most of the lesions were on the arms, legs, the front of the torso and on a band across the lower back — in other words places where the sufferers could reach to scratch.
Drugs were detected in hair samples from about half the people who submitted hair for analysis. The study notes that the sensation of bugs under the skin can be a side-effect of the use of some drugs (prescription and non-prescription) as well as of drug withdrawal. But the authors said they didn't know if that played a role here. Some of the drugs might have been taken as treatment for the Morgellons' symptoms, they said.
The study is not likely to satisfy people who believe they suffer from a condition that has become know as Morgellons. And they may see the coded message the CDC refused to spell out clearly.
"I'm not sure what we can do," said Eberhard. "We did a study. We tried to do it unbiased. Tried to collect the data. Let the data speak for itself."
He tried to put a positive spin on the study's outcome for sufferers, saying it should help them get better care faster.
"I think it's actually one of those cases where a negative is actually a very big step forward," Eberhard said. "It should be very helpful to both patients and to their health-care providers to be reassured that they really don't need to start at the beginning and look for infectious causes and links to the environment."