Have We Forgotten What Tics Are? A Re-Exploration of Tic Phenomenology in Youth with Primary Tics.

BACKGROUND

The first systematic description of tics in a large sample was in 1978.

OBJECTIVES

To assess the phenomenology of tics in youth and investigate how age and sex influence tic phenomenology.

METHODS

Children and adolescents with primary tic disorders have been prospectively included in our Registry in Calgary, Canada, since 2017. We examined tic frequency and distribution using the Yale Global Tic Severity Scale, differences between sexes, and changes in tic severity with age and with mental health comorbidities.

RESULTS

A total of 203 children and adolescents with primary tic disorders were included (76.4% males; mean age = 10.7 years, 95% CI = 10.3-11.1). At first assessment, the most common simple motor tics were eye blinking (57%), head jerks/movements (51%), eye movements (48%) and mouth movements (46%); 86% had at least one simple facial tic. The most frequent complex motor tics were tic-related compulsive behaviors (19%). Throat clearing was the most common simple phonic tic (42%); 5% only had coprolalia. Females had higher frequency and intensity of motor tics than males ( = 0.032 and  = 0.006, respectively), associated with greater tic-related impairment ( = 0.045). Age was positively correlated with the Total Tic Severity Score (coefficient 0.54,  = 0.005), along with the number, frequency and intensity of motor tics but not with their complexity. Psychiatric comorbidities were associated with greater tic severity.

CONCLUSIONS

Our study suggests that age and sex affect clinical presentation in youth with tics. The phenomenology of tics in our sample was similar to the 1978 description of tics, and contrasts with functional tic-like behaviors.