The mother of a man charged in the Sunday shooting death of a church pastor blames Lyme disease for his mental problems. However, leading disease specialists say there's no convincing evidence linking the tickborne ailment to such violent behavior.
"Lyme disease doesn't cause people to shoot people," said Dr. Eugene Shapiro, a Lyme disease specialist at Yale University.
He recalled an ax attack in Connecticut in which the perpetrator "pleaded Lyme disease defense. That didn't fly."
The most common Lyme symptoms, caused by bacteria spread by the tiny deer tick, include a bullseye-shaped skin rash and fever. Most people recover with antibiotics, although some symptoms can persist.
According to the federal Centers for Disease Control and Prevention's Web site, Lyme disease can spread to the bones, heart and nervous system if not treated. It can cause brain inflammation and in rare cases, problems with concentration, short-term memory and sleep disturbances.
Sometimes there is severe headache and neck stiffness, which can be treated by antibiotics, Shapiro said.
Occasionally, nervous system problems can develop months or even years after a tick bite, including irritability and nerve damage in the arms and legs, according to the National Institutes of Health.
But Shapiro said that while there are isolated reports of hallucinations and psychotic illness blamed on Lyme disease, these are controversial. He said these cases likely involve people with pre-existing mental problems or who were misdiagnosed and never had Lyme disease.
Some patient-advocacy groups use the term "Lyme rage" to explain aggressive psychiatric symptoms. Dr. Paul Auwaerter, an infectious disease specialist at Johns Hopkins medical school, noted that the condition was even implicated in a highly publicized chimp attack last month that severely injured a Connecticut woman; the animal was said to have Lyme disease.
But at least in humans, mental illness is much more common than Lyme disease, and it would be "extraordinarily rare" to develop a true psychosis from the disease, Auwaerter said.
Dr. Gary Wormser, infectious diseases chief at New York Medical College in Valhalla, said he has done research showing that in areas where the Lyme tick is rampant, psychiatric patients are not more likely than other people to have Lyme disease.
Auwaerter said believers tend to be community doctors in the trenches — primary care physicians in areas where Lyme ticks are prevalent and who diagnose Lyme disease based on symptoms rather than blood tests.
These include Dr. Daniel Cameron, an internist in Westchester County, New York, where Lyme disease is common. Cameron is president of the International Lyme and Associated Diseases Society, a group of mostly primary care doctors.
He said he has had many patients with Lyme disease who complain of psychiatric problems, including anxiety, panic and aggression. Some, usually young people, have resorted to violence including hitting family members, he said.
He defended diagnosing patients based on symptoms, saying blood tests aren't perfect. And, Cameron argued, research suggesting there is no link is not strong enough "to dismiss the medical and psychiatric issues that we see in our practices."
On the Net:
National Institutes of Health: http://www.ninds.nih.gov/disorders/lyme/lyme.htm