Cognitive tics in Gilles de la Tourette syndrome

BACKGROUND Gilles de la Tourette syndrome (GTS) is characterized by motor and vocal tics. Cognitive tics (CTs) have been rarely recognized as part of GTS symptomatology and their prevalence and associates have not been systematically investigated. OBJECTIVES The aim of the study was to assess the incidence and clinical associations of CTs in a group of patients with GTS. METHODS We examined 227 consecutive GTS patients aged 5–50 years old (78.4% males). The median duration of GTS was 4 years (IQR: 3–7) in children and 18 years (IQR: 12–23) in adults. The patients were evaluated for GTS and comorbid mental disorders according to the DSM-IV-TR and DSM-5. CTs were defined as brief, sudden, recurring involuntary thoughts, analogous to typically recognized complex vocal tics and diagnosed during the interview. Correlations between CTs and clinical variables were evaluated in two analyses, lifetime and current. Children and adult groups were compared. RESULTS Lifetime CTs were reported by 48 patients (21.1%), in 33 of the cases at the time of evaluation. The median age at onset of CTs was 13.5 years (IQR 9.3–16). Five mental phenomena were evaluated: echolalia (n = 17), coprolalia (n = 16), palilalia (n = 13), counting (n = 11), repeating of words in mind (n = 7). In the multivariable analysis of lifetime CTs, tic severity (p = 0.025) and significant social skill problems (p = 0.050) demonstrated correlation, while for current CTs only tic severity (p = 0.028) and anxiety disorder (p = 0.028) remained significant. In logistic regression model for age groups, in children only age was a factor significantly associated with lifetime CTs (p = 0.033), whereas in adults there were no statistically significant associations with lifetime CTs. For current CTs, none of the variables reached statistical significance in children, while only anxiety disorder was a predictor of current CTs in adults (p = 0.018). CONCLUSIONS CTs are a part of tic spectrum with a substantial impact of comorbid psychiatric disorders. CTs are a late and age-related symptom of GTS.