Tourette Syndrome: Why Is It Overlooked In Girls?

Published recently in journal Neurology, a recent study analyzed of underdiagnosed or diagnosed later in girls for Tourette syndrome to boys. As per the study by the University of Florida and Harvard Medical School with other international collaborators, Tourette syndrome is more frequently underdiagnosed in girls as compared to boys.

The study used the Tourette Association of America International Consortium for Genetics data set to better understand sex differences and health outcomes for the neurodevelopmental disorder.

How was the study conducted?

The researchers analyzed histories of over 2000 people, to be specific, it was 2,109 with Tourette and 294 with persistent motor or vocal tic disorder (PMVT). While the two conditions are similar, people with Tourette have tics that are motor and vocal with sudden, repetitive and involuntary movements or sound. Whereas people with PMVT have either motor or vocal tics, but not both types.

What did the study find?

“We found that these disorders tend to be underdiagnosed in females, potentially leading to delays in appropriate treatment, which can include medication or behavioral therapies or both,” said Carol Mathews, M.D., chair of UF psychiatry and co-author of the study.

“While we’ve known for some time that males are three times more likely than females to have Tourette, PMVT — which is slightly less severe — has a different sex ratio,” Mathews said. “Males are only two times more likely to have PMVT. Yet females continue to be underdiagnosed with both Tourette and PMVT.”

The study also found that girls with Tourette had lower tic severity and were less likely to have received a formal diagnosis prior to the study, 61% compared to 77% for boys. On average, it takes three years for girls to be diagnosed with Tourette, two years for boys. Average age at diagnosis was 13.3 years old for girls and 10.7 for boys. Symptom onset of Tourette was slightly later in girls - average of 6.5 years old compared to 6 for boys. For PMVT, however it was flipped, with 8.9 years old for boys and 7.9 for girls.

What is Tourette syndrome?

As per the Tourette Association of America, it is a neurodevelopmental disorder that affects children, adolescents and adults, characterized by sudden, involuntary movements and/or sounds called tics. Tics can range from mild/inconsequential to moderate and severe, and are disabling in some cases.

The Tourette Association of America notes: "Tourette Syndrome is one type of Tic Disorder. Tics are the primary symptoms of a group of childhood-onset neurological conditions known collectively as Tic Disorders and individually as Tourette Syndrome (TS), Persistent (Chronic) Motor or Vocal Tic Disorder, and Provisional Tic Disorder. These three Tic Disorders are named based on the types of tics present (motor, vocal/phonic, or both) and by the length of time that the tics have been present."

What is PMVT?

Persistent (chronic) motor or vocal tic disorder is one of the five tic disorder in the Diagnostic and Statistical Manual of Mental Disorder, which has an onset before 18. One defining characteristic of PMVT is that someone with this disorder can have either motor or vocal tics but not both.

Among the vocal tics, it may be grunting, barking, snorting, coughing, sniffing, throat clearing, repeating others, repeating words, humming. uttering inappropriate words, hissing, and yelling.

Whereas the motor tics include, jerking, blinking, grimacing, head banging, shoulder shrugging, foot tapping, imitating someone else’s movements, lip biting, nose wrinkling, frowning, head turning, sticking out the tongue, squatting, kicking, jumping, hopping, and rocking back and forth.