Overview

Tourette disorder (TD) is a neurodevelopmental disorder characterized by motor and vocal tics. It is often associated with multiple psychiatric comorbidities involving a high degree of impulsivity such as obsessive-compulsive disorders (OCD), attention-deficit hyperactivity disorders (ADHD), and intermittent explosive disorders (IED). Although a substantial body of clinical studies have emphasized the role of the dopamine system in motor symptoms, little is known about how the serotonergic (5-HT) system modulate both cognitive and affective abilities in TD. Several lines of evidence suggest that different 5-HT receptor subtypes may constitute a crucial factor in the development and maintenance of different symptoms. Because abnormal 5-HT2A receptor bindings have been reported in patients with TD and aripiprazole (drug of first choice) is a 5-HT2A antagonist, we hypothesize that 5-HT2A receptors may play an important role in regulating psychiatric symptoms in TD such as those characterized by impulsive behaviors. To investigate the involvement of 5-HT2A receptors in TD, we propose to perform a multimodal imaging study with 20 adult patients (ON and OFF treatment). Neuroimaging data will be collected with a hybrid system that simultaneously combines the positron emission tomography (PET) and the functional magnetic resonance imaging (fMRI). A highly selective PET radiotracer ([18F]-altanserin) will map 5-HT2A receptor bindings in the whole brain, while fMRI will provide detail information regarding the altered brain activities.

Eligibility

• Inclusion Criteria * :
  • Male or Female
  • Diagnosed with a Tourette Disorder following the DSM-5
  • Age between 18-65 years
  • Member of a social security scheme in France
  • Freely-given informed consent to participate to this study (written form)
  • With a current treatment by aripiprazole already scheduled
  • With Tics compatible with TEP/fMRI exams
  • Having (for women only) effective contraception throughout participation in the study.

Exclusion Criteria * :

• Male or Female
• A serious not controlled psychiatric comorbidity
• A serious, evolving or debilitating pathology with a potential influence on the study
• Drug-taking with serotonergic effects (e.g., amphetamine, cocaine, MDMA, SSRIs, mianserin)
• Contraindication for fMRI and PET (e.g., pacemaker, ferromagnetic implant, claustrophobia)
• Women breastfeeding
• Protected or restricted person (administratively or in judicial terms)
• Participants to another study with radiations or radiotracers since less of one year, participants to a concomitant study
• Do not speak french