The Phenomenology of Attention-Deficit/Hyperactivity Disorder in Tourette Syndrome

Abstract

AbstractThis chapter focuses on the complex epidemiological and phenomenological aspects of attention-deficit/hyperactivity disorder (ADHD) in Tourette syndrome (TS). Research on this topic is relatively recent and elucidated the high importance of comorbidity in TS and the need for an early assessment of ADHD in TS. Several observational studies have confirmed that ADHD is the most common comorbidity in TS, possibly anticipating TS onset and influencing the male gender predominance of TS. ADHD exerts a negative impact on externalizing and internalizing symptoms, as well as on psychosocial functioning and quality of life in TS. The impact of comorbid ADHD upon sleep disturbances in TS remain a neglected issue. Approaches to model the coexistence of TS and ADHD are still ongoing. Whereas basic neurobiological aspects fit with an additive model, complex cognitive functioning supports an interactive model. Specific pathophysiological features for TS plus ADHD have not yet been identified, but common heritability between TS and ADHD might be explained, at least in part, by the comorbidity of ADHD and obsessive–compulsive disorder. Future studies on the phenomenology of TS plus ADHD should consider not only the core symptoms of TS and ADHD but also obsessive–compulsive behavior traits, emotional aspects, neuropsychological aspects, quality of life, early risk factors, resilience, and other possible mediators and moderators.