Can Red Blood Cell and Platelet Parameters Be Associated With Inflammation in Children With Tic Disorder?

OBJECTIVE

Tic disorder (TD) is one of the neurodevelopmental disorders and its etiology has not been fully elucidated. Complete blood count (CBC) values have been used as indicators of a systemic inflammatory response. In our study, we aimed to assess hemogram parameters in drug-naive, comorbidity-free children with TD compared with controls.

METHODS

This retrospective study included 62 drug-naive children with TD who had undergone CBC within one month prior to the study. A control group of 48 healthy children, matched for age and gender, without any organic or psychiatric disorders, was included. Statistical analysis was performed by using IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, New York, United States).  Results: Hematocrit (p = 0.044), mean corpuscular volume (p = 0.002), platelet count (p = 0.011), and plateletcrit (p = 0.031) values were significantly higher in the TD group, whereas mean corpuscular hemoglobin concentration (p = 0.00) was significantly lower in the TD group. Additionally, a significant negative correlation was observed between the duration of illness and platelet (p = 0.05, r=-0.282), plateletcrit (p = 0.038, r = -0.295), and neutrophil count (p = 0.006, r = -0.391), while a positive correlation was found between the duration of illness and eosinophil count (p = 0.018, r = 0.336).

CONCLUSION

The results revealed several significant differences in hemogram parameters between TD patients and the control group. These may suggest the role of inflammation and/or other underlying mechanisms in TD and may inspire new studies. Future studies with larger and more homogeneous samples, including comprehensive inflammatory markers, may contribute to a deeper understanding of the relationship between inflammation and TD.

Correlates and clinical implications of tic suppressibility

Purpose of review

Tic disorders are common in the pediatric population and are differentiated from other movement disorders by tic suppressibility. Understanding the mechanism of tic suppression may provide new insights to the pathophysiology of tic disorders. This article highlights clinical phenomenology and neuronal correlates of tic suppressibility.

Recent findings

Recent studies suggest that tic suppressibility exists in children shortly after onset of their tics. Moreover, those who are better able to suppress their tics have better tic outcomes. Interoceptive awareness and automatic action inhibition may be involved in tic suppression.

Summary

We illustrate a possible underlying mechanism of tic suppressibility and its clinical correlations and implications. New concepts such as interoceptive awareness and action inhibition may help explain tic disorders. Further study will be useful to fill remaining knowledge gaps.

Tourette's disorder in children and adolescents

Tourette's disorder (TD) is one of the five American Psychiatric Association's 2013 Diagnostic and Statistical Manual of Mental Disorders (DSM-5) classifications of tic disorders. Eponymously linked with the noted 19th century French physician, Gilles de la Tourette [1857-1904], this disorder is identified in 0.3% to 0.7% of the population. It is characterized as a familial neuropsychiatric condition with multiple motor tics and vocal tics (one or more) present for more than 1 year with varying severity. The underlying pathophysiology involves dysfunctional activity of the basal ganglia and circuitry of the frontal cortex as well as dorsolateral striatum deficits. Contributory factors include genetic features interacting with milieu influences. A number of comorbid disorders are seen including obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD). Concepts of management are considered including behavioral therapy and pharmacologic approaches with alpha-adrenoceptor agonists, atypical antipsychotics (AAs), haloperidol, pimozide and others. Other management includes botulinum injections and deep brain stimulation in adults.

Tic Suppression in Children With Recent-Onset Tics Predicts 1-Year Tic Outcome

Successful voluntary tic suppression is a key component of the behavioral interventions that are used to treat tic disorders. This study aimed to examine tic suppression in children with recent-onset tics and determine whether the capacity to suppress tics predicts future tic severity. We tested 45 children (30 male, mean age 7.74 years) with recent-onset tics (mean 3.47 months prior to the first study visit; baseline) and re-examined each child at the 12-month anniversary of the first recognized tic (follow-up). At the baseline visit, children performed a tic suppression task with several conditions: tic freely, inhibit tics given a verbal request, and inhibit tics in the presence of a reward. At the baseline visit, children with tics for only a few months could suppress their tics, and tic suppression was especially successful when they received an immediate and contingent reward. Additionally, the ability to suppress tics in the presence of a reward predicted tic severity at follow-up. These findings suggest that better inhibitory control of tics within months of tic onset may be an important predictor of future tic symptom outcome.