Introduction

This article is meant to disseminate recent scientific progress on Gilles de la Tourette Syndrome (TS). Through the end of the year, it will be a work in progress, maintained as a web page on the Authorea online authoring platform. Around the end of the year, we plan to submit it for publication as the annual update for the Tics collection on F1000Research.

Methods

We searched PubMed from time to time during 2017 using the search strategy “("Tic Disorders"[MeSH] OR Tourette NOT Tourette[AU]) AND 2017[PDAT] NOT 1950:2016[PDAT]”. On 27 Dec 2017 this search returned 196 citations. Colleagues also recommended articles, and we attended selected medical conferences. We selected material for this review subjectively, guided by our judgment of possible future impact on the field.

Results

Phenomenology and natural history

Martino and colleagues summarize common non-tic symptoms in people with tic disorders \citep{28805580}\citep{28289551} describe 16 people with Tourette syndrome who had experienced a clinical remission or marked improvement of more than 1 year's duration, followed by symptomatic worsening as adults, leading them again to seek treatment. On average the "latent period" (the absence or substantial reduction in tics) had lasted 16 years. Seven of them had worse tics when returning for care than they recalled as children. New substance use was reported as a trigger for exacerbation in 5 patients. This report strengthens the evidence that even long-lasting symptomatic improvement in tic disorders may not always be permanent. A large Danish study reports follow-up data 6 years after enrolling 314 children and teenagers with Tourette syndrome \citep{28335874}. Most patients improved over time, but almost a quarter of those over age 16 still had severe tics, and only a sixth had no tics.

Epidemiology

A report on 606 patients with a movement disorder starting in childhood produced an estimate for tic onset of 7.4 ± 3.8 years with a mean delay to diagnosis of 9.9 ± 11 years \citep{Baumer:2016}
Mortality risk is elevated in TS and other tic disorders, with or without comorbidities (https://f1000.com/prime/727436422).
In a very large epidemiological study, tic disorders in adults were associated with a four-fold higher risk of suicide, with the risk not explained by other psychiatric illness such as major depression \citep{27773353}. The same group found a 7- to 10-fold higher risk of completed suicide in people with OCD, even after controlling for comorbid diagnoses \citep{27431293}