Research supports advantages associated with Tourette syndrome.
A study of 11 adults with TS found that they could visually bisect a line more accurately than control subjects (have a ticcer hang all your pictures quickly without a tape measure).
A study of eight children with Tourette syndrome found they were much quicker at certain mental grammar skills than children without TS. The underlying brain differences that lead to tics may also lead to "other rapid behaviors, including the cognitive processing of rule-governed forms in language and other types of procedural knowledge". Michael Ullman, PhD, said, "These children were particularly fast, as well as largely accurate, in certain language tasks. This tells us that their cognitive processing may be altered in ways we have only begun to explore, and moreover in a manner that may provide them with performance that is actually enhanced compared [to] that of typically-developing children". Six of the eight children studied had "TS-only"; two of the eight had ADHD, one of whom also had OCD.
Martha Denckla, MD, of Johns Hopkins University School of Medicine reports that there is evidence supporting the clinical folklore that children with "TS-only" (40% of children with TS, according to Denckla) have unusual gifts; neuropsychological studies reveal advantages in children with TS-only. A study of full-scale IQ showed that children with TS-only had higher IQ scores than predicted by statistical models, relative to their parents' intelligence. She says, "there is reason to give some credence to common clinical lore, namely, that these children are unusually intellectually gifted youngsters who show no cognitive deficits." She also reported that none of the children with pure Tourette syndrome (TS without co-occurring conditions) had learning disabilities.
Another study of motor function found that 76% of children with TS-only were faster than average on timed motor coordination; similar results were not found among children with TS with co-occurring attention deficit hyperactivity disorder.
A controlled study of 13 people with TS found that cognitive control was enhanced in people with Tourette's (without ADHD) because a lifetime of suppressing tics results in more efficient control of inhibitions. A follow-up study confirmed the result that individuals with Tourette's exhibit greater cognitive control than age-matched subjects. The enhanced cognitive control in the TS group was found in spite of there being a statistically-significant slight advantage in the average IQ of the age-matched controls. Subjects with ADHD were excluded from the sample and controls were also screened to eliminate ADHD.
When ADHD co-occurs with TS, social, behavioral and academic difficulties may be present. Many studies have shown that behavioral disturbances seen in TS are actually caused by co-occurring ADHD and not the TS itself, and that learning disabilities may be secondary to ADHD as well. Denckla argues that there is a case for categorizing "pure TS" separately from "TS plus ADHD" and that "it is important to inform the parents of [children with pure Tourette syndrome], who comprise 40% of all children with Tourette syndrome, that their future is not burdened with the same issues as those of the remaining 60% of children who have comorbid ADHD with Tourette syndrome." She also says that treatment for TS plus ADHD need not differ from treatment for ADHD alone.