Abstract
Bidirectional overlap between attention-deficit/hyperactivity disorder (ADHD) and tic disorders has long been described. Twenty percent of individuals with ADHD may meet diagnostic criteria for a tic disorder, and more than 60 % of children ages 6–17 with Tourette’s disorder (TD) in the community had also been diagnosed with ADHD/ADD. While comorbid presentation of ADHD and tic disorders is firmly established, underlying genetic and pathophysiologic mechanisms need additional investigation. Inhibition is a core deficit in both ADHD and tic disorders, and research suggests a diffuse process in the brain involving corticostriatothalamicortical (CSTC) pathways in the basal ganglia, striatum, and frontal lobes. The complex presentation of these patients requires comprehensive evaluation and prioritization of treatment goals. Most studies indicate that ADHD places a greater burden on patients than do tics. Optimal patient outcomes may depend on management of both ADHD symptoms and tics when they co-occur. Research in the past decade has shown that these conditions can be safely treated simultaneously.