Subtypes of tic disorders in children and adolescents: based on clinical characteristics

Abstract

Background: Tic disorder (TD) is a diverse neurodevelopmental disorder with various symptoms and comorbidities. Traditional classifications based on age onset and duration fail to adequately characterize the full clinical features of TD. This study aims to redefine TD subtypes by a comprehensive analysis of clinical features and comorbidities.

Methods: We assessed 139 children and adolescents aged 6-18 years using 14 scales covering 43 dimensions. The k-means clustering algorithm was used to identify distinct TD subtypes. Differences between these subtypes were analyzed using t-tests and network analysis, with high expected influence (EI) metric representing key symptoms within each subtype.

Results: We identified two distinct subtypes of TD, with 21.6% of participants classified as subtype1 and 78.4% as subtype2. Subtype1 exhibited more severe symptoms across TD, obsessive-compulsive spectrum disorders, and attention deficit hyperactivity disorder assessments compared to subtype2, with significant differences observed in 81.4% of the scale features. Network analysis revealed differences in core symptoms between the two subtypes; subtype1 primarily involved hyperactivity and vital activities, whereas subtype2 primarily involved attention deficit, hyperactivity and conduct. Furthermore, comparisons with DSM-5 classifications revealed distinct patterns, indicating the novel nature of the identified subtypes.

Conclusion: Our study identified two novel TD subtypes, highlighting its heterogeneity. Subtype 1 had more severe attention deficits and impulsivity, requiring comprehensive treatment, while subtype 2 had milder symptoms, focusing on support and monitoring. These findings provide insights into TD classification and may help refine treatment strategies. However, the cross-sectional design limits causal interpretations, and reliance on parent-reported data may introduce bias.

Keywords: Clinical characteristics; Cluster analysis; Subtype classification; Tic disorder.

Fig. 1

Heatmap of TD related characteristics scale in 2-cluster solution. The heatmap consisted of 43 dimensions of clinical features of all participants, and the data were standardized and divided into 30 subtype1 and 109 subtype2 subjects according to k-means clustering analysis. Abbreviation: YGTSS, Yale Global Tic Severity Scale; PTQ, Parent Tic Questionnaire; PUTS, Premonitory Urge for Tics Scale; MOVES, Motor Obsessive-compulsive and Vocal Evaluation Scale; OCD, obsessive-compulsive disorder; GTS-QOL, Gilles de la Tourette Syndrome Quality of Life Scale; SPAS, Sensory Phenomena Assessment Scale; CY-BOCS, Children Yale-Brown Obsessive-Compulsive Scale; OCI-R, Obsessive-Compulsive Inventory-Revised; CBRS, Conners’ Comprehensive Behavior Rating Scales Parent Questionnaire; HI, hyperactive impulsive; SDQ, Strengths and Difficulties Questionnaire; C-ADHD-RS, Child ADHD Rating Scale; WWPARS, Werry-Weiss-Peters Activity Rating Scale; SNAP-IV-26, Swanson Nolan and Pelham-IV-26 Rating Scales; AD, Attention deficit; OD, Oppositional defiance; WFIRS-P, Weiss Functional Impairment Scale Parent Form

Fig. 2

The scale differences between the two subtypes. Values represent the mean and standard deviation of scores in each dimension. Order the p-values after FDR correction from smallest to largest, from left to right. Note: * and *** represent the corrected p value < 0.05 and < 0.001 of subtype1 and 2 feature values of each dimension’s difference. Abbreviation: CBRS, Conners’ Comprehensive Behavior Rating Scales Parent Questionnaire; SNAP-IV-26, Swanson Nolan and Pelham-IV-26 Rating Scales; AD, Attention deficit; OD, Oppositional defiance; HI, hyperactive impulsive; C-ADHD-RS, Child ADHD Rating Scale; MOVES, Motor Obsessive-compulsive and Vocal Evaluation Scale; GTS-QOL, Gilles de la Tourette Syndrome Quality of Life Scale; WWPARS, Werry-Weiss-Peters Activity Rating Scale; WFIRS-P, Weiss Functional Impairment Scale Parent Form; OCI-R, Obsessive-Compulsive Inventory-Revised; SDQ, Strengths and Difficulties Questionnaire; OCD, obsessive-compulsive disorder; SPAS, Sensory Phenomena Assessment Scale; PTQ, Parent Tic Questionnaire; PUTS, Premonitory Urge for Tics Scale; YGTSS, Yale Global Tic Severity Scale; CY-BOCS, Children Yale-Brown Obsessive-Compulsive Scale

Fig. 3

Network analysis of two new subtypes. (A) Constructing a network of clinical features for each subtype (FDR corrected p < 0.05). (B) Expected Influence. EI values for 35 dimensions, ranking from largest to smallest. Abbreviation: PTQ, Parent Tic Questionnaire; PUTS, Premonitory Urge for Tics Scale; MOVES, Motor Obsessive-compulsive and Vocal Evaluation Scale; OCD, obsessive-compulsive disorder; GTS-QOL, Gilles de la Tourette Syndrome Quality of Life Scale; SPAS, Sensory Phenomena Assessment Scale; OCI-R, Obsessive-Compulsive Inventory-Revised; CBRS, Conners’ Comprehensive Behavior Rating Scales Parent Questionnaire; HI, hyperactive impulsive; SDQ, Strengths and Difficulties Questionnaire; C-ADHD-RS, Child ADHD Rating Scale; WWPARS, Werry-Weiss-Peters Activity Rating Scale; SNAP-IV-26, Swanson Nolan and Pelham-IV-26 Rating Scales; AD, Attention deficit; OD, Oppositional defiance; WFIRS-P, Weiss Functional Impairment Scale Parent Form

Fig. 4

Comparison between two new TD subtypes and DSM-5 TD classifications. Abbreviation: TS: Tourette syndrome; CTD: Chronic tic disorder; TTD: Transient tic disorder

Fig. 5

Comparison of average number of follow-up visits between two new subtypes. *, p < 0.05