WASHINGTON—Three out of every 1,000 children between 6 and 17 in the US have been diagnosed with Tourette Syndrome (TS), the Centers for Disease Control and Prevention found in its first-ever national estimate of the neurological disorder.

Tourette Syndrome (TS) is an inherited disorder characterized by multiple involuntary movements, called motor tics, and uncontrollable vocalizations called vocal or phonic tics. The onset of TS and tics typically occurs when a child is 6 to 8 years old, with diagnosis usually occurring around this time as well. Although TS and tics might appear, disappear, and reappear, these disorders are considered chronic.

Prior to the study, health officials did not have a national estimate indicating how prevalent the condition is in the US. “Prevalence is just one of those required indicators that helps us gauge the impact of a disorder in the United States or a community. For the first time, we know now that there are about 148,000 American youth living with TS in America,” said Susanna Visser, MS, a CDC epidemiologist and one of the study authors.

The study analyzed data from interviews with parents (or guardians) from 91,642 households from April 2007 through July 2008 that was collected through the National Survey of Children’s Health (NSCH). Interviews were completed in 66% of identified households with children.

Visser acknowledged that the prevalence of TS could be higher than what the national study found. Prior smaller studies had put the prevalence of TS at about 6 per 1,000. “We were relying on a previous diagnosis of TS as reported by the parent. There are probably many children out there that are full blown TS and meet the criteria, but have not quite reached the diagnosis for a variety reasons,” Visser said.

Visser said that some of the reasons why a child may not have been diagnosed with the condition include lack of access to care, or even the preference of the child’s family to not seek diagnosis.

TS In Youth

The study found that a TS diagnosis is three times more common in boys than in girls, and approximately twice as common in children between 12-17 years as those aged 6-12 years. Among children with TS, 27% were reported as having moderate or severe TS and 79% of children had also been diagnosed with at least one additional mental health or neurodevelopmental condition.

Non-Hispanic white children were more than twice as likely as non-Hispanic black children or Hispanic children to have a parent-reported TS diagnosis, according to the study. Access to care, or the family’s preference to not seek a diagnosis, may account for the higher rate of diagnoses among non-Hispanic white children. “Our next step is to really dive into access to care and find out,” Visser said. “For example, are Latino families who have really great health care coverage more likely than Latino families without great health care coverage to get a diagnosis?”

Visser said that it is important that TS symptoms are investigated. Health care providers should be aware, she said, that the study found that among children with TS, 79% had been diagnosed with at least one additional mental health or neurodevelopmental condition. “Those co-occurring conditions may actually provide more impairment that the TS itself. This is a red flag. So if the child is vocally ticking or has some sort of a motor tick, dig a little deeper,” Visser said.

The study can be found in the June 5th issue of CDC’s Morbidity and Mortality Weekly Report.