.

Epidemiology

Transient environmental effects on tic severity

Tic suppression

\citet{28502600}

Sensory phenomena and premonitory urges

The Committee on Research of the American Neuropsychiatric Association published a systematic review on the neurobiology of the premonitory urge in TS \cite{28121259}.

Other

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 \cite{27773353}.
Autism spectrum rating scale scores are elevated in TS \cite{28647013a}. This is mostly but not entirely explained by elevations in the RRB (restricted interests and repetitive behaviors) subscale, which may be indicating tics rather than other stereotypic movements. The presence of OCD was associated with higher scores on the social cognition and RRB subscales.
Review of screening instruments and rating scales for tic disorders \cite{28071825}, and comments \cite{28436544}\cite{28436554}.
A study of 45 children with TS supported the typical antecedent–behavior–consequence behavioral psychology model \cite{27044052}. Specifically, consequences of tics, "such as receiving accommodations or attention from others," explained significantly more variance in tic severity than did the child's level of separation anxiety, though the latter was also a significant factor. This study provides supportive evidence for the approach taken by "CBIT-Jr," a behavior therapy designed for younger children with TS \cite{RN9681}.

Etiology

A national database study of parental psychopathology \cite{28335873}.

Genetics

Large mixed genetic sample yielded two heritable collections of symptoms that cross diagnostic boundaries, here named symmetry (including some other O-C symptoms) and disinhibition (including complex verbal tics) \cite{27809572}.

Epigenetics

Environmental risk factors