The overlap between TS/CT, OCD and ADHD were also examined for all subjects who completed both the tic and OCD/ADHD questionnaires (n = 6,607) (Figure 2). 8.2% of TS Intermediate cases had both ADHD and OCD, whereas only 2.2% of all OCD cases and 2.5% of all ADHD cases had all three disorders (Figure 2a). In addition, 69% of TS Intermediate cases and approximately 80% of all OCD or ADHD cases had an isolated disorder without either of the other two diagnoses. This relatively low rate of overlapping TS, OCD, and ADHD was present even when considering all chronic tic disorders (TS or CT Intermediate) or when restricting the sample to the more stringent TS Narrow definition (Figure 2b and Figure S1, available online).
