Patient characteristics
We identified 119 pediatric patients (89 males, 30 females) who were diagnosed with tic disorders during the time frame of this study. The mean age of tic onset was 6.9 years (range, 1–14) and the mean age at the time of diagnosis of tic disorders was 8 years (range, 1–17). Of the 119 patients, ninety-two (77.3%) were diagnosed with provisional tic disorder and 19 (16%) with Tourette syndrome. The remaining 8 patients (6.7%) were diagnosed with chronic motor or vocal tic disorder.
The most common, first-presenting tics were eye blinking (50.4%), followed by jaw or lip movement (29.4%) and throat clearing (29.4%). In addition, head-turning or nodding (28.6%), eyeball rolling (26.9%), and arm movement (26.9%) were frequently observed (Table 1). Of the 119 patients, thirty-seven (31.1%) had at least one co-occurring neuropsychiatric disorder at the time of diagnosis of tic disorders. The most common comorbid neuropsychiatric condition was ADHD (10.9%), followed by anxiety disorder (7.6%), developmental delay or intellectual disability (6.7%), and epilepsy (6.7%) (Table 2). Eighty of 119 patients (67.2%) were treated with anti-tic medication: antipsychotics only (n = 72), antidepressants only (n = 1), and combined antipsychotics and antidepressants (n = 7). The remaining thirty-nine patients (32.8%) received behavioral therapy.
[TABLE 1 TO BE PLACED HERE]
[TABLE 2 TO BE PLACED HERE]
Tic severity and associated impairment
Seventy-six (63.9%) children in the sample were reported to have mild symptoms, thirty (25.2%) had moderate symptoms, and the remaining thirteen (10.9%) had severe symptoms. A comparison of demographic and clinical characteristics of patients with mild tics and those with moderate to severe tics is shown in Table 3. No significant differences were found between patients diagnosed with mild tics compared to moderate/severe tics with regard to gender, age at symptom onset, age at diagnosis, or time between symptom onset and diagnosis. Subtypes of tic disorders, types of initial tics, and presence of neuropsychiatric comorbidities were not associated with tic severity. Based on multivariate regression analysis, gender, age at symptom onset, age at diagnosis, time between symptom onset and diagnosis, subtypes of tic disorders, types of initial tics, and presence of neuropsychiatric comorbidities, were not significantly related to tic severity. However, patients with moderate to severe tics were significantly more likely to have tics that were noticeable to strangers and that interfered with their daily functioning, compared to those with mild tics. When the patients were divided into three groups according to subtypes of tic disorders, no significant differences in gender, age at symptom onset, age at diagnosis, time between symptom onset and diagnosis, types of initial tics, and presence of neuropsychiatric comorbidities were observed between patients with different tic severities. Compared to those with mild tics, patients with provisional tic disorder and those with moderate to severe tics, were significantly more likely to have tics that were noticeable to strangers and that interfered with their daily functioning.
[TABLE 3 TO BE PLACED HERE]
Factors influencing time to diagnosis
The mean lag time from when tics were first noticed to diagnosis of tic disorders was 13.3 months (range, 0.25–132). Gender differences in lag time to diagnosis were observed, 10.0 months for females compared to 8.0 months for males (p = 0.05). No significant difference was found in the time to diagnosis between patients with the presence of neuropsychiatric comorbidities, and those without (p = 0.91). In addition, age at symptom onset was not correlated with the time to diagnosis (Spearman’s ρ = –0.14, p = 0.11). The mean time to diagnosis was shorter in patients whose initial tics were motor tics only, compared to those with vocal tics only and combined motor and vocal tics, with a mean of 5.6 months (range, 0.25–24), 21.3 months (range, 0.25–96), and 18.9 months (range, 0.25–132), respectively (p <0.05). Tic severity was negatively correlated with diagnostic lag time (Spearman’s ρ = –0.18, p <0.05), that is, the more severe the tics, the less time that elapsed before a diagnosis.
Predictors of follow-up outcomes
The patients were followed up for an average of 20.2 months (range, 0.1–88.5) after the diagnosis of tic disorders. Of 119 patients, ninety-nine (83.2%) reported a greater than 50% reduction in tic severity, and twenty (16.8%) reported no changes in the tic symptoms at follow-up. To determine the factors related to favorable outcomes, we compared the characteristics of patients who achieved more than 50% reduction in symptoms with those who had no change in tic severity. Gender, age of onset, age at diagnosis, time interval between onset and diagnosis, subtypes of tic disorders, initial symptoms, tic severity at diagnosis, presence of neuropsychiatric comorbidities, and treatment utilization did not influence likelihood of favorable outcomes (Table 4). Based on multivariate regression analysis, gender, age of onset, age at diagnosis, time interval between onset and diagnosis, subtypes of tic disorders, initial symptoms, tic severity at diagnosis, presence of neuropsychiatric comorbidities, and treatment utilization, were not significantly related to clinical outcomes. When the patients were divided into three groups according to subtypes of tic disorders, no significant differences regarding gender, age of onset, age at diagnosis, time interval between onset and diagnosis, initial tic symptoms, tic severity at diagnosis, presence of neuropsychiatric comorbidities, or treatment utilization were observed between patients who showed different outcomes.
[TABLE 4 TO BE PLACED HERE]