Etiology

Genetics and epigenetics

In autism, genetic effects on several early neurodevelopmental traits are better explained indirectly by their effect on cognitive ability and educational attainment \citep{Hegemann_2024}.
GWAS identifies 30 loci associated with OCD {DOI 10.1101/2024.03.13.24304161}.

Environmental risk factors

"The Challenge of Examining Social Determinants of Health in People Living with Tourette Syndrome" \citep{Dy_Hollins_2023}.

Post-mortem studies

"[W]e performed single cell transcriptomic and chromatin accessibility analyses of the caudate nucleus from 6 adult TS and 6 control post-mortem brains. ... interneurons were decreased by roughly 50% in TS brains, while no difference was observed for other cell types. ... Differential gene expression analysis suggested that mitochondrial function, and specifically oxidative metabolism, in MSN and synaptic function in interneurons are both impaired in TS subjects, while microglia display strong activation of immune response pathways." \citep{Wang_2024}

Pathophysiology

Electrophysiology

Neuroimaging studies

Interesting fMRI study design looking at brain activity related to situations that trigger tics and tic imagery \citep{38191475}.
"Functional connectivity of the nucleus accumbens predicts clinical course in treated and non-responder adult ADHD" \citep{Zaher_2024}.

Animal models

"Phonic Tics in a Rat Model of Tourette Syndrome Enable Research on Symptom-Based DBS" \citep{Sagalajev_2023}. [Note: preprint appeared in 2023]

Other

Treatment

\citet{38247265} summarize the pill placebo response rate in tic disorders. They find a pooled effect size of −0.79, and note that 44% of study participants reported adverse events on placebo. These results are important for designing future treatment studies in TS.

Psychological interventions

Tic suppression-based treatments for tics have been criticized (mostly by those who do not do behavior therapy) as likely to provoke tic substitution or to be too difficult. The group that performed the first large CBIT trial in children 11 years ago followed up with those participants, now adults, to ask about such experiences then or since \citep{38557310}. The great majority of study participants recalled no such negative experiences, and importantly those who did were no more likely to have been in the CBIT arm vs. the control therapy arm. This study adds to substantial prior data showing that such negative experiences are rare, and hopefully can put to rest these concerns.