Strep Infections May Be Associated with ADHD
May 12, 2000 -- In the past, some researchers have suggested there is a
relationship between common strep infections and neuro-psychiatric problems,
such as Tourette syndrome and obsessive-compulsive disorders. Now a Yale
research team says there appears to be a much stronger relationship between
strep infections and attention-deficit/hyperactivity disorders.
"Over half the children with Tourette syndrome also have ADHD," says
researcher Paul Lombroso, MD. "Perhaps the group that has all three
conditions may be particularly vulnerable to streptococcal infections."
Lombroso is an associate professor of child psychiatry at the Yale University
School of Medicine in New Haven, Conn.
The research was designed to look at the possibility that Tourette syndrome
and obsessive-compulsive disorders (OCD) might be caused or aggravated by
recent strep infections. "In fact, we found the clearest association was
not with those conditions but with a subgroup who had ADHD," Lombroso says.
"This was an unexpected finding."
Clearly, he says, more research is needed. "This is a preliminary study,
so these results must be replicated and expanded."
The researchers looked at strep antibodies in about 100 people ages 7 to 55
who had OCD, Tourette syndrome, or ADHD, as well as a group of people who
didn't have any of these conditions. They found that patients with ADHD had
high levels of strep antibodies, suggesting a recent infection. They didn't
find similar elevated levels of antibodies in people who had Tourette syndrome
or OCD, but did not have ADHD.
This study looked at patients during one particular "slice of time,"
Lombroso says. To clarify the relationship among strep infections and childhood
neuro-psychiatric disorders, researchers need to follow patients for two or
three years. The Yale group has now begun such a long-term study.
"This is an interesting paper," says Mark Wolraich, MD, who reviewed
the study for WebMD. He says longer-term research focusing on children who only
have ADHD is needed. "The issue is certainly worth pursuing," says
Wolraich, a professor of pediatrics at the Vanderbilt University School of
Medicine in Nashville, Tenn.
"Sometimes things do occur which we don't expect, so we always need to
be open to new ideas," says Howard Schubiner, MD, who also reviewed the
study for WebMD. But he cautions that all that the researchers have found is an
association in a few people. Schubiner is professor of pediatrics, internal
medicine, and psychiatry at Wayne State University School of Medicine in
Meanwhile, the study's authors caution against treating children with OCD or
ADHD with antibiotics in hope of improving those conditions. Of course, if a
child has a sore throat or an ear infection due to strep, antibiotics are
appropriate. But the researchers say they see no point in trying to use
antibiotics as a general preventative measure until we know far more about the
relationship among these three conditions and strep infections.
Wolraich and Schubiner say they agree with that conclusion. "Even if
ADHD did turn out to be due to an immunological reaction to a strep infection,
or to any infection, antibiotic treatment would not necessarily help, since you
have to treat the immune reaction, not the infection itself," Schubiner
The research was funded by the National Institute of Mental Health, the
National Institutes of Health, and the Stanley Foundation of Muscatine,