Tic expression is sensitive to environmental/behavioural factors. Hence, identifying exacerbating factors can be beneficial. However, the influence of any factor is highly individualized, with more studies being required for exploration of treatment addressing each patient's unique tics. The study will recruit 60 children and adolescents aged 7-15 with Chronic Tic Disorders (CTDs), including Tourette's Disorder, Chronic Motor Tic Disorder, and Chronic Vocal Tic Disorder. Each participant will be required to attend 2 separate sessions. The initial assessment will measure tic severity, comorbid disorders, and cognitive functioning, in order to establish eligibility and to measure variables related to tic reactivity. Also, each will receive a detailed Functional Assessment Interview (FAI), to identify environmental events exacerbating tics. Later, the results of each FAI will be validated by a Confirmatory Experimental Analysis (CEA), where tics are monitored during introduction and removal of factors reported on the FAI to exacerbate tics. FAI validity is limited, and improper use can worsen tics.This study, then, aims to test and develop the FAI, in order to augment effectiveness of behavioural aspects of CTD treatment. This is especially important in light of newly discovered side effects and interactions of medications. The study will take place at Schneider Children's Medical Centre of Israel, the only highly specialized care hospital in Israel and the Middle East dedicated exclusively to paediatric treatment, being open to every child irrespective of religion, race, or nationality. This is a joint project with UCLA and UWM. The study is relevant to the objectives of the Specific Programme and the Work Programme on numerous levels, promoting reintegration of a physician researcher, safety of illness treatments, empowerment of patients as individuals, and research reaching all regions of the European Union and associated countries.