9 February 2007
Strep Implicated In Psychiatric Problems
by Kate Melville
Researchers have found an intriguing association between streptococcal infection in children and behaviors that are more usually associated with neurological disorders. The new findings add weight to the existence of PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus), which some scientists think are responsible for a host of problems such as tics, personality change, anxiety and obsessive-compulsive disorder.
The new study, appearing in the Journal of Biological Psychiatry, describes how the researchers found an association between strep infections and neuropsychiatric symptoms within a group of students in the Florida public school system. Previously, research in the PANDAS field focused on children already diagnosed with psychiatric disorders.
Strep throat and other streptococcal infections are common in schools and environments where bacteria are easily spread. In peak season - December and January - more than one in three children will be infected. Not all of the children will have sore throat symptoms, but they carry the bacteria and can infect others.
"The medical perspective has always been that the carrier states are fairly benign, but maybe they are not as benign as we thought," said UF's Tanya Murphy. "That's not to suggest that these states are increasing children's risk for rheumatic fever or other problems that can develop after an infection, but maybe there is a milder spectrum of effects that shouldn't always be ignored."
The study found that about 26 percent of children who had two or more strep infections displayed abnormal symptoms compared with 17 percent of children who were not infected or infected only once. "We were looking for patterns of association in just a standard group of children who ranged in age from 3 to 12 years," Murphy said. "During the fall months when there are more strep infections, after a short time lag, there are increased behavioral symptoms - enough to indicate an association. We did not assess the children for particular neuropsychiatric disorders, so we're not saying actual disorders were present in the children, but the symptoms were there."
"This is exactly the kind of study that was needed," commented Loren Mell, of the University of Chicago. Mell was part of a team that published findings in 2005 that showed strep infections were associated with increased risk of obsessive-compulsive disorder, Tourette's syndrome or tic disorder in children who were already diagnosed with a psychiatric disorder.
Murphy speculates that streptococcal infections may cause the body's immune system to interact with brain cells that cause psychiatric symptoms in a small percentage of young patients. "Further study to show prospectively that group A strep infections lead to neuropsychiatric disorders as determined by the Diagnostic and Statistical Manual of Mental Disorders criteria would help substantiate their findings," Mell noted. "Interestingly, their results are similar to ours in the sense that having multiple infections appears to confer a much higher risk of these disorders."
Source: University of Florida Health Science Center