Etiology

Genetics

Epigenetics

Environmental risk factors

 

Pathophysiology

Animal models

Pathological studies

Electrophysiology

Neuroimaging studies

Pharmacological studies

Interesting hypothesis, "Allopregnanolone: The missing link to explain the eects of stress on tic exacerbation?" \citep{34423500a}
Sturm et al. (2021) investigated inhibitory control abitilies in 24 TS patients, 139 ADHD patients, 19 TD+ADHD patients and 59 typically developing controls aged 9-14 years. Inhibitory control was measured using common neurocognitive tasks : Attentional Network Task (ANT), Stop Signal Task (SST), Delis-Kaplan Stroop task, Go-Nogo task. Surprisingly, their results did not confirm the inhibitory control deficit that had previously been found in TS or TS + ADHD patients (for review Morand-Beaulieu et al, 2017). But the originality of this paper was to evaluate how inhibitory control deficit, tics severity (YGTSS), ADHD symptoms severity (SWAN), and subjective tic suppressibility (item 10, PUTS), contribute to objective tic suppressibility (tic suppression paradigm, Himle & Woods 2005). The authors found that the only predictor of performance in the tic suppression paradigm was subjective tic suppressibility, and that inhibitory control deficit, tics and ADHD severity, had no effect. As objective tic suppression is known to be a potential mechanism of behavioral treatment response for TS patients, this finding have interesting clinical implications.