Neurodevelopmental disorders as a risk factor for temporomandibular disorder: evidence from Mendelian randomization studies

Objective: This study aims to clarify the incidence rate of temporomandibular joint disease in patients with mental disorders. Methods: Data extracted from the Psychiatric Genomics Consortium and FinnGen databases employed the Mendelian Randomization (MR) method to assess the associations of three neurodevelopmental disorders (NDDs)-Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD), and Tourette's Disorder (TD)-as exposure factors with Temporomandibular Disorder (TMD). The analysis used a two-sample MR design, employing the Inverse Variance Weighted (IVW) method to evaluate the relationships between these disorders and Temporomandibular Disorder. Sensitivity analysis and heterogeneity assessments were conducted. Potential confounding factors like low birth weight, childhood obesity, and body mass index were controlled for. Results: The study found that ADHD significantly increased the risks for TMD (OR = 1.2342, 95%CI (1.1448-1.3307), p < 0.00001), TMD (including avohilmo) (OR = 1.1244, 95%CI (1.0643-1.1880), p = 0.00003), TMD-related pain (OR = 1.1590, 95%CI (1.0964-1.2252), p < 0.00001), and TMD-related muscular pain associated with fibromyalgia (OR = 1.1815, 95%CI (1.1133-1.2538), p < 0.00001), while other disorders did not show significant causal relationships. Conclusion: This study reveals the elevated risk of various TMD aspects due to ADHD. Furthermore, we discuss the link between low vitamin D levels ADHD and TMD. Future research should address these limitations and delve further into the complex interactions between ADHD, ASD, TD, and TMD.

Tonic Tics in Gilles de la Tourette Syndrome

AIM

Tonic tics (TTs) are a part of a clinical picture of Gilles de la Tourette syndrome (GTS) and manifest themselves as sustained and isometric contraction of a muscle group devoid of the movement effect or accompanied by only slight visible motion. The aim of this study was to evaluate the prevalence and phenomenology of TTs, and to assess the clinical associations of TTs with tic severity and comorbidities in patients with GTS.

METHODS

We performed a one-time registration study in a cohort of 241 consecutive outpatients with GTS aged 5 to 50 years (188 males, 153 patients under the age of 18 years). All patients were personally interviewed and examined.

RESULTS

TTs occurred in 85.2% of adults and 63.9% of children and adolescents. Most frequently reported types of TTs were tensing of the abdomen (58.7%), neck (52.7%), and upper limbs (50.3%). Multivariate statistical analysis showed a significant correlation between TTs and the total number of simple tics, total number of complex tics, and age at evaluation. In the group of children and adolescents, an additional significant variable was the duration of GTS. In the group of adults, significant parameters were total number of simple tics, total number of complex tics, peak tic severity ever experienced, premonitory urges, and the presence of dystonic tics.

CONCLUSION

TTs belong to the tic spectrum, common and early symptoms of GTS, are associated with overall a greater number of tics which are more severe, and with more comorbidities.

TS-EUROTRAIN: A European-Wide Investigation and Training Network on the Etiology and Pathophysiology of Gilles de la Tourette Syndrome

Gilles de la Tourette Syndrome (GTS) is characterized by the presence of multiple motor and phonic tics with a fluctuating course of intensity, frequency, and severity. Up to 90% of patients with GTS present with comorbid conditions, most commonly attention-deficit/hyperactivity disorder (ADHD), and obsessive-compulsive disorder (OCD), thus providing an excellent model for the exploration of shared etiology across disorders. TS-EUROTRAIN (FP7-PEOPLE-2012-ITN, Grant Agr.No. 316978) is a Marie Curie Initial Training Network (http://ts-eurotrain.eu) that aims to elucidate the complex etiology of the onset and clinical course of GTS, investigate the neurobiological underpinnings of GTS and related disorders, translate research findings into clinical applications, and establish a pan-European infrastructure for the study of GTS. This includes the challenges of (i) assembling a large genetic database for the evaluation of the genetic architecture with high statistical power; (ii) exploring the role of gene-environment interactions including the effects of epigenetic phenomena; (iii) employing endophenotype-based approaches to understand the shared etiology between GTS, OCD, and ADHD; (iv) establishing a developmental animal model for GTS; (v) gaining new insights into the neurobiological mechanisms of GTS via cross-sectional and longitudinal neuroimaging studies; and (vi) partaking in outreach activities including the dissemination of scientific knowledge about GTS to the public. Fifteen partners from academia and industry and 12 PhD candidates pursue the project. Here, we aim to share the design of an interdisciplinary project, showcasing the potential of large-scale collaborative efforts in the field of GTS. Our ultimate aims are to elucidate the complex etiology and neurobiological underpinnings of GTS, translate research findings into clinical applications, and establish Pan-European infrastructure for the study of GTS and associated disorders.

Behavior therapy for tics in children: acute and long-term effects on psychiatric and psychosocial functioning

Children (n = 126) ages 9 to 17 years with chronic tic or Tourette disorder were randomly assigned to receive either behavior therapy or a control treatment over 10 weeks. This study examined acute effects of behavior therapy on secondary psychiatric symptoms and psychosocial functioning and long-term effects on these measures for behavior therapy responders only. Baseline and end point assessments conducted by a masked independent evaluator assessed several secondary psychiatric symptoms and measures of psychosocial functioning. Responders to behavior therapy at the end of the acute phase were reassessed at 3-month and 6-month follow-up. Children in the behavior therapy and control conditions did not differentially improve on secondary psychiatric or psychosocial outcome measures at the end of the acute phase. At 6-month posttreatment, positive response to behavior therapy was associated with decreased anxiety, disruptive behavior, and family strain and improved social functioning. Behavior therapy is a tic-specific treatment for children with tic disorders.

Open-label study comparing the efficacy and tolerability of aripiprazole and haloperidol in the treatment of pediatric tic disorders

Due to its unique pharmacodynamic properties of dopamine partial agonist activity, and its association with few and mild side effects, aripiprazole is a candidate atypical antipsychotic for patients with tic disorders. This open-label study compared the efficacy and tolerability of aripiprazole with haloperidol, a typical antipsychotic widely used to treat patients with tic disorders. Forty-eight children and adolescents with tic disorders were recruited from the outpatient clinic at South Korea and treated with aripiprazole (initial dose, 5.0 mg/d; maximum dose 20 mg/d) or haloperidol (initial dose, 0.75 mg/d; maximum dose, 4.5 mg/d) for 8 weeks. Treatment efficacy was measured using the yale global tic severity scale (YGTSS), and tolerability was measured using the extrapyramidal symptom rating scale (ESRS) and an adverse effects checklist. Total tic scores as measured by the YGTSS decreased over time in both groups (p < 0.001) without any significant differences between groups. ESRS scores were significantly higher in the haloperidol group during the 4 weeks after commencement of medication (p < 0.05). These results indicate that aripiprazole may be a promising drug in the treatment of children and adolescents with tic disorders. Further controlled studies are needed to determine the efficacy and tolerability of aripiprazole in these patients.