This study describes our systematic literature review documenting outcomes associated with persistent tic disorders (PTDs) and summarizes 15 articles comparing health care use between individuals with PTDs and a comparison group without PTDs. Only 2 studies included adults and only one study stratified findings by sociodemographic characteristics, precluding conclusions on health care disparities. Most children with PTDs had access to routine care, similar to children without PTDs, but needed and used more specialty health care, including mental health services, compared to children without PTDs. Improving identification and management of PTDs in primary care settings may improve health care access for individuals with PTDs.
Key points
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Most children with persistent tic disorders (PTDs) have access to routine health care, similar to children without PTDs.
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Children with PTDs use more specialty care including mental health care compared to children without PTDs.
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The literature on health care use among individuals with PTDs that have comparison groups without PTDs is limited, particularly for adults. Additionally, only one of the included studies examined health care needs or use by sociodemographic characteristics.
Introduction
Approximately 1 in 50 children has a persistent tic disorder (PTD), including Tourette syndrome (TS). A PTD diagnosis requires the presence of motor and/or vocal tics before age 18 years that persist for at least 1 year and are not due to another medical condition. Although PTD symptoms may lessen in severity or resolve by young adulthood, they can persist throughout the lifespan. PTDs are associated with negative outcomes across the lifespan related to education, family and social functioning, quality of life, and engagement in health risk behaviors. Public health can play a role in supporting individuals with PTDs through the provision of the 10 essential public health services, which include monitoring health status, diagnosing and investigating health problems, and ensuring the availability of essential health services.
PTD outcomes can be improved by early identification of PTDs and receipt of evidence-based treatment when needed. , Approximately half of children with TS are undiagnosed. Underdiagnosis of TS may be more common in Black and Hispanic populations, , suggesting possible disparities in health care access. Among US children diagnosed with TS, half saw at least 3 health care providers before being diagnosed. A lack of knowledge or comfort in the identification and treatment of tic disorders may contribute to underdiagnosis. ,
Identification of PTDs requires access to health care, and treatment of PTDs often necessitates access to specialty health care. , Professional organizations in the United States, Canada, and Europe have published diagnostic and treatment guidelines that describe evidence-based practice for caring for children and adults with PTDs. , , , The guidelines each describe the assessment of PTDs, recommend psychoeducation about PTDs for individuals with these disorders and their families, and review the evidence base for behavioral and pharmacologic treatments as well as deep brain stimulation.
To inform improved health and well-being among individuals with PTDs, the authors conducted a systematic literature review focusing on health-related indicators and outcomes associated with tic disorders (herein referred to as outcomes) addressable through public health activities. This article summarizes the literature related to health care access, health care needs, and health care use among children and adults with PTDs compared to those without PTDs. The information from this review can inform future research, practice, and policies to improve identification and treatment of tic disorders.
Methods
Literature Review
We conducted a broad literature search to identify outcomes associated with PTDs; the full search is described here, as well as findings related to health care; other outcomes will be summarized in future studies. The literature search was conducted on July 6, 2023, using Medline, Embase, PsycInfo, Cochrane library, CINAHL, and Scopus. Although we proposed several a priori associated outcomes of interest (eg, health care, social, education), our search was intentionally broad to capture emergent outcomes in the literature. The Medline search terms were “tic disorders/OR TS/OR Tics/OR (Tourette∗ OR tic disorder∗ OR tics OR (involuntary ADJ2 [twitch∗ OR movement∗ OR sound∗ OR vocalization∗ OR noise∗ OR gestur∗])).ti,ab,kf. AND (Public health OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden).ti,ab,kf,hw. OR ep.fs OR px.fs” ( Table 1 specifies all search terms). The search was limited to English language publications with no restrictions on year of publication, age of individuals with PTDs, or geographic location, and identified 6510 articles.
| Database | Strategy |
|---|---|
| Medline (OVID) 1946– | tic disorders/OR tourette syndrome/OR Tics/OR (Tourette∗ OR tic disorder∗ OR tics OR (involuntary ADJ2 (twitch∗ OR movement∗ OR sound∗ OR vocalization∗ OR noise∗ OR gestur∗))).ti,ab,kf. AND (Public health OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden).ti,ab,kf,hw. OR ep.fs OR px.fs Limit to English Language; Abstract Available |
| Embase (OVID) 1974– | tic/OR Gilles de la tourette syndrome/OR (Tourette∗ OR tic disorder∗ OR tics OR (involuntary ADJ2 (twitch∗ OR movement∗ OR sound∗ OR vocalization∗ OR noise∗ OR gestur∗))).ti,ab,kw. AND (Public health OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden).ti,ab,kw,hw. OR ep.fs Limit to English Language Remove Medline Records Abstract Available |
| PsycInfo (OVID) | tic disorders/OR tourette syndrome/OR Tics/OR (Tourette∗ OR tic disorder∗ OR tics OR (involuntary ADJ2 (twitch∗ OR movement∗ OR sound∗ OR vocalization∗ OR noise∗ OR gestur∗))).ti,ab,id. AND (Public health OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden).ti,ab,sh,id. Limit to English Language; Abstract Available |
| Cochrane Library | [mh “Tourette Syndrome”] OR [mh “tic disorders”] OR [mh Tics] OR (Tourette∗ OR “tic disorder” OR “tic disorders” OR tics OR (involuntary NEAR/2 (twitch∗ OR movement∗ OR sound∗ OR vocalization∗ OR noise∗ OR gestur∗))) AND (“Public health” OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden):ti,ab,kw Abstract Available |
| CINAHL (EBSCOHost) | (MH “Tourette Syndrome”) OR (MH “Tic”) OR (Tourette∗ OR “tic disorder∗” OR tics OR (involuntary N2 (twitch∗ OR movement∗ OR sound∗ OR vocalization∗ OR noise∗ OR gestur∗))) AND (TI (“Public health” OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden)) OR (AB (“Public health” OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden)) OR (SU (“Public health” OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden)) Limiters – English Language; Exclude MEDLINE records; Abstract Available |
| Scopus | TITLE-ABS-KEY(Tourette∗ OR “tic disorder∗” OR (involuntary W/2 (twitch∗ OR movement∗ OR sound∗ OR vocalization∗ OR noise∗ OR gestur∗))) AND TITLE-ABS-KEY(“Public health” OR epidemiolog∗ OR surveillance OR survey∗ OR “quality of life” OR QoL OR cost∗ OR impact∗ OR burden) AND NOT INDEX(medline) Abstract Available |
Title and Abstract Screening
The titles and abstracts of all 6510 articles were screened in Covidence by 2 independent reviewers, with disagreements adjudicated by a third reviewer. No automation tools were used to identify articles for inclusion or exclusion. Articles were excluded using the following criteria: (1) the study involved nonhuman participants; (2) the title or abstract explicitly stated that the article was a research protocol only; (3) the article focused on nonrelevant “tics” retrieved by the search terms (eg, tick, trauma-informed care [TIC]); (4) the article focused on tardive dyskinesia, Parkinson’s disease, schizophrenia, Huntington’s disease, dystonias, functional tics, psychogenic tics, transient tics, or provisional tics, rather than PTDs; (5) the article was a book review, video, poster, slide, or personal account; (6) the article was not peer reviewed (eg, dissertations); (7) the article reported on a study with less than 10 participants; and (8) conference abstracts. This resulted in the exclusion of 4076 articles ( Fig. 1 ).
Full-text Screening
The research team conducted full-text screening on the remaining 2434 articles. Eligible outcomes were those identified as potentially modifiable through public health activities ( Fig. 2 ). Overarching categories and examples of eligible and ineligible outcomes within the health care needs and use category were identified based on existing knowledge and continuously refined over the course of the review. All changes were then retrospectively applied to all previously screened articles. Exclusion criteria at this stage included those applied to the title and abstract review and (1) articles with no eligible outcomes (see below and Fig. 2 ); (2) reviews and meta-analyses; and (3) surveys of health care providers or educators about their experiences with PTDs. We also excluded articles focusing on prevalence of co-occurring mental, behavioral, and developmental disorders (MBDDs), and symptoms of these disorders (eg, behavioral problems, executive function), among individuals with PTDs to avoid duplication with the substantial literature documenting the prevalence of these disorders among individuals with PTDs. , , , One exception was that we included studies of substance-use disorders and substance use as eligible health risk behaviors. Examples of other ineligible outcomes included studies on the knowledge of tic disorders, instrument psychometrics, prevalence of PTDs, neurobiology of tic disorders, and studies focused on characteristics of tic disorders (eg, type of tic, severity). Most articles were reviewed by 2 reviewers, including in all cases where these exclusion criteria were not clearly present.
We excluded 1826 articles at this stage. As part of this review, we identified 5 additional eligible articles that were missed in the initial literature search or screened out in an earlier stage; these articles were identified by reviewing methodology papers cited by articles during full-text review. This resulted in 613 articles for potential extraction.
Full-text Extraction
Full-text extraction focused on studies with comparison groups without PTDs from any geographic location published in 2003 or later. Two reviewers conducted extraction in Covidence; a third reviewer conducted a consensus review. Data extracted included study location, year(s) of data collection, whether the sample was recruited from a tic disorder specialty clinic, types of PTDs (eg, TS only), how PTDs were identified including which assessments and diagnostic criteria were used, type of comparison group (eg, general population, normative data), source of data for outcome measures (eg, parent-report, administrative data), type of study (eg, cohort, case-control), participant characteristics (eg, age, sex, race/ethnicity), and eligible outcomes.
Several decisions for extracting data consistently across articles were documented. Treatment prevalence was included when it was a key study outcome and not when it was included as part of the sample description. In articles with multiple comparison groups, the group that was most similar to the general population was selected. In articles with multiple PTD groups (eg, TS only, TS and ADHD, ADHD only), we coded TS only compared to a comparison group or, if no true comparison group, compared with the co-occurring condition only (eg, ADHD only) group. We included studies with PTDs and transient tic disorders that could not be disaggregated and refer to these as PTDs; groups are shown in Table 2 . Cross-sectional studies and studies where the outcomes were measured after the PTD diagnosis were included, while studies where the eligible outcome was a predictor of tic onset or severity and measured before tic onset were excluded. For example, articles examining cross-sectional association of infections and PTDs were included, but if the infection was documented before tic onset or a change in tic severity, the article was excluded. We focused on prevalence estimates when available, or unadjusted (or least adjusted) results for comparability across studies.
| Author, Year | Tic Disorders Included, PTD Assessment/Criteria (Number of People in the Study with PTD) | Comparison Population (n) | Age at Outcome (years) | Male (%) | Race/Ethnicity (% or n) | Sample Type, Years of Data Collection (Country) |
|---|---|---|---|---|---|---|
| Bitsko et al, 2013 | Current TS; parent report (147) | Children without TS or asthma (57,416) | 6–17 | TS: 78.9% Comparison: 50.4% | TS: 82% W; 9.2% H Comparison: 73.6% W; 19.6% H | Nationally representative survey, NSCH 2007 (U.S.) |
| Bitsko et al, 2014 | Current TS; parent report (153) | Children without TS (∼65,000) | 6–17 | TS: 128 male, 25 female | TS: 114 W(NH), 6 B(NH), 13 h Total: 43,075 W(NH), 6168 B(NH), 8051 h | Nationally representative survey NSCH 2011–2012 (U.S.) |
| Cooper et al, 2003 | Current TS; Assessed using National Hospital Interview Schedule, DSM-III-R (26) | Children with asthma (26) | 7–16 | TS: 76.9% Comparison: 61.5% | TS: 100% W Comparison: 42.3% W, 57.7% O | Tourette specialty clinic, nd (UK) |
| Cubo et al, 2013 | Current TS, chronic motor/vocal, transient tic disorders; Diagnostic assessment, DSM-IV-TR (162) | Children without tics (245) | 6–16 | TD: 68.5% Comparison: 60.7% | TS: 92.5% W Comparison: 88.4% W | School-based, 2007–2009 (Spain) |
| Cubo et al, 2017 | Current TS, chronic motor/vocal, transient, nonspecific tics; Diagnostic assessment, DSM-IV-TR (61) | Children without tics and who had grade retention since 2013 study (156) | 11–17 | TD: 55.4% Comparison: 55.4% | NR | School-based, 2010–2014 (Spain) |
| Gadow et al, 2009 | Current CMTD + ADHD; YGTSS, GTRS, direct observation, family history, assessment of research criteria (66, including 62 TS & 4 CMTD) | Children with ADHD only (66) | Avg (SD) 8.6 (1.8) CMTD+ ADHD 8.0 (1.4) comparison | CMTD+ ADHD: 77%, ADHD only: 89% | CMTD+ ADHD: 88% W, 12% O ADHD only: 89% W, 11% O | Psychiatry clinic, community clinic, schools, media, parent-support groups, nd (U.S.) |
| Giacobbe et al, 2021 | Current Tic disorder; medical record review for diagnosis (67) | Underserved (Medicaid insurance or self-pay) patients with movement disorders, includes tic disorder group (355) | Avg (SD) 19.9 (11.6) tics, 44.4 (20.5) total | TD: 67.2% Total: 50.4% | NR | Academic tertiary movement disorders clinic, 2002–2017 (U.S.) |
| Jalenques et al, 2017 | Current TS; Previous diagnosis, clinical assessment, DSM-IV-TR (75) | Children without TS (75) | 12–18 | TS: 60% Comparison: 60% | NR | Community-based, 2010–2013 (France) |
| Khalifa et al, 2005 | Current TS (25), chronic motor (34), chronic vocal (24); Clinical assessment, DSM-IV | Children with transient tics (25) | 7–15 | NR | NR | Community-based, nd (Sweden) |
| Leeb et al, 2020 | Current TS; parent-report (107) | Children with no MBDD (21,664) | 12–17 | NR | NR | Nationally representative survey, NSCH 2016–2017 (U.S.) |
| Olfson et al, 2011 | Current TS, Chronic tic disorder; ICD-9 codes from health care claims (Publicly insured: 5414 TS, 787 CTD; Privately insured: 8071 TS, 1642 CTD) | Children without tic disorders; (Publicly insured: 10,237,261; privately insured: 16,102,562) | 4–18 | Publicly insured: 51.1%, Privately insured: 51.1% | All publicly insured: 34.6% W, 28.7% B, 29.1% H, 7.6% O (NR for privately insured) | MarketScan Research Databases, Medicaid Analytic Extract File (health care claims), 2000–2007 (U.S.) |
| Scahill et al, 2006 | Current TS plus CTD plus transient/provisional; DSM-III-R, Clinical assessment (DISC-R) (21) | Children without TS or other psychiatric disorder; (43) | 6–12 | TD: 61.9% Comparison: 51.1% | NR | Community-based, 1991 (U.S.) |
| Smith et al, 2023 | Current TS; caregiver report (42) | Typically developing children; (34) | 5–17 | TS: 78.6% Comparison: 29.4% | NR | Anonymous online survey, nd (U.K.) |
| Yang et al, 2017 | Current TS; self-report (122) | Total population-based sample, includes TS group; (122,884) | ≥ 12 | TS: 74.7% Comparison: 49.3% | NR | Nationally representative survey, CCHS 2010–2011 (Canada) |
| Zinna et al, 2021 | Current TS plus CTD; ICD-10 codes from medical records (43) | Children without TS; (175) | ≤ 13 | PTD: 67.4% Comparison: 50.9% | NR | Psychiatry/neurology/psychology clinic based, 2009–2019 (U.K.) |
During this stage, we also excluded 6 articles with substantial or complete overlap of participants and eligible outcomes; in these cases, we kept the articles with larger sample sizes or with the most representative PTD and comparison groups (eg, not stratified by an additional variable). This resulted in 167 articles for inclusion. Fifteen of these articles reported on outcomes related to health care (eg, access, treatment) and are summarized here.
Current evidence
Characteristics of the 15 articles are summarized in Table 2 and Table 3 . All studies were from North America (7 from United States, 1 from Canada) or Europe (3 United Kingdom, 2 Spain, 1 France, 1 Sweden). Only 2 studies included adults. , Seven studies assessed clinical criteria for PTDs, 3 identified PTDs using medical records or claims data, and 5 identified PTDs based on caregiver or self-report of a previous diagnosis. Thirteen studies reported the sex distribution for individuals with PTDs; of these, the PTD group was at least 75% male in 6 studies. Of the 6 studies that reported on race or ethnicity, over 80% of the PTD group was White in 5 of the studies; in the sixth study, race/ethnicity was only reported for the full sample using health care claims data. Seven of the 15 articles included only TS, while the other 8 articles included a combination of tic disorders. Two studies reported findings for TS and chronic tic disorder separately. , Outcomes were measured using parent-report or self-report in 12 studies, data from health care records in 2 studies, and a combination of parent-report and self-report and health care records in one study (see Table 3 ). Four studies from North America were nationally representative, and a fifth included health care claims data from multiple US states; 5 studies were population-based with recruitment from schools (n = 2) or the community (n = 3), 4 were clinic based, and one used a convenience sample to complete an online survey. Nine studies included less than 100 individuals with PTDs and only one included more than 200 individuals with PTDs.
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