Sleep problems were explored in two studies. Colreavy and colleagues found that sleep patterns was more impacted by the pandemic in children with TS than in typically developing children \citep{Colreavy2023}. Using a naturalistic, longitudinal approach, Keenan and colleagues found that children with TS spend significantly more time in bed, have increased sleep onset latency, reduced sleep efficiency, and lower subjective sleep quality compared to healthy controls, whereas sleep time is comparable \citep{Keenan2024}. In contrast to clinical observations, self-reported tic severity was not related to increased sleep onset latency. More than 80% of children with TS fulfilled diagnostic criteria for a sleep disorder, highlighting the importance for screening for sleep difficulties in clinical routine.
Kurvits and colleagues investigated the prevalence of compulsive sexual behaviors and paraphilic interests in adults with chronic tic disorders \citep{Kurvits2023}. In contrast to previous reports, these symptoms were found at the same rate as in the general population. There was also no association with the use of antipsychotics, though in other populations case reports have linked partial dopamine agonists to disinhibited behavior. ADHD was a risk factor for paraphilic interests and compulsive sexual behaviors.
The Danish TS Study Group published the results of a longitudinal study investigating substance use in pediatric patients with TS \citep{Andersen2023}. Comorbid ADHD and lower socioeconomic status of the guardian predicted higher risk for tobacco smoking, while coexisting OCD was a protective factor.
Tygesen and colleagues compared fine motor skills in children with TS with their healthy siblings and matched healthy controls, but failed to demonstrate any differences between these three groups \citep{Tygesen2023}.
Nilles and colleagues published a fascinating review on comorbid developmental stuttering (childhood-onset fluency disorder) and TS. Tics and stuttering are the most common 'habit disorders'. They both have a male predominance and can significantly alter quality of life. Also, they both fluctuate and often go into remission after childhood. Of note, as clinicians seeing individuals with TS know, there are speech-blocking or stuttering-like tics that can be difficult to distinguish from developmental stuttering. More work disentangling the similarities and differences between both disorders is needed \citep{Nilles2023a}.
Stereotypies are the major hyperkinetic movements disorders associated with tics during the developmental period, and also a major differential diagnosis. Cavanna and colleagues presented a systematic literature review on comorbid tics and stereotypies based on six original studies that were deemed of sufficient quality and size. 23% of patients diagnosed with stereotypies had comorbid tics; conversely, the prevalence of stereotypies in individuals with TS was estimated at 8%. Interestingly, the authors point out the possibility that treatment-refractory repetitive movements in adults with TS could represent persistent stereotypies \citep{Cavanna2024}.