Overall, tic disorders occur more commonly in children than in adults and more so in males than in females. They are observed with higher frequency in populations with special educational needs.[1]Jankovic J, Lang AE. Movement disorders: diagnosis and assessment. In: Bradley WG, Daroff RB, Fenichel GM, et al. Neurology in clinical practice. Principles of diagnosis and management. 4th ed. Philadelphia, PA: Elsevier; 2004:313-5.[4]Knight T, Steeves T, Day L, et al. Prevalence of tic disorders: a systematic review and meta-analysis. Pediatr Neurol. 2012 Aug;47(2):77-90.
http://www.ncbi.nlm.nih.gov/pubmed/22759682?tool=bestpractice.com
[5]Leivonen S, Voutilainen A, Hinkka-Yli-Salomäki S, et al. A nationwide register study of the characteristics, incidence and validity of diagnosed Tourette syndrome and other tic disorders. Acta Paediatr. 2014 Sep;103(9):984-90.
http://www.ncbi.nlm.nih.gov/pubmed/24862980?tool=bestpractice.com
Provisional tic disorders (tics present for <1 year) appear to be very common in childhood and have been estimated to occur in up to 20% of primary school children.[6]Scahill L, Specht M, Page C. The prevalence of tic disorders and clinical characteristics in children. J Obsessive Compuls Relat Disord. 2014 Oct 1;3(4):394-400.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243175
http://www.ncbi.nlm.nih.gov/pubmed/25436183?tool=bestpractice.com
[7]Black KJ, Black ER, Greene DJ, et al. Provisional tic disorder: what to tell parents when their child first starts ticcing. F1000Res. 2016 Apr 18;5:696.
http://f1000research.com/articles/5-696/v1
http://www.ncbi.nlm.nih.gov/pubmed/27158458?tool=bestpractice.com
Chronic tic disorder (motor or vocal tic[s] present for >1 year) occurs less commonly; population-based surveys indicate that the prevalence of chronic tic disorders is 1% to 3%.[2]Singer HS. Tourette syndrome and its associated neurobehavioral problems. In: Swaiman KF, Ashwal S, Ferriero DM. Pediatric neurology: principles and practice. 4th ed. Philadelphia, PA: Elsevier; 2006:887-98.[8]Alves HL, Quagliato EM. The prevalence of tic disorders in children and adolescents in Brazil. Arq Neuropsiquiatr. 2014 Dec;72(12):942-8.
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-282X2014005040174&lng=en&nrm=iso&tlng=en
http://www.ncbi.nlm.nih.gov/pubmed/25465775?tool=bestpractice.com
Tourette's syndrome (multiple motor tics and one or more vocal tics present for >1 year; also called Tourette's disorder) has a population-based prevalence in children of 0.3% to 0.9%; prevalence is higher in males, with a male to female ratio of 3:1, and the mean age of onset is between 6 and 7 years.[2]Singer HS. Tourette syndrome and its associated neurobehavioral problems. In: Swaiman KF, Ashwal S, Ferriero DM. Pediatric neurology: principles and practice. 4th ed. Philadelphia, PA: Elsevier; 2006:887-98.[4]Knight T, Steeves T, Day L, et al. Prevalence of tic disorders: a systematic review and meta-analysis. Pediatr Neurol. 2012 Aug;47(2):77-90.
http://www.ncbi.nlm.nih.gov/pubmed/22759682?tool=bestpractice.com
[5]Leivonen S, Voutilainen A, Hinkka-Yli-Salomäki S, et al. A nationwide register study of the characteristics, incidence and validity of diagnosed Tourette syndrome and other tic disorders. Acta Paediatr. 2014 Sep;103(9):984-90.
http://www.ncbi.nlm.nih.gov/pubmed/24862980?tool=bestpractice.com
[9]Scharf JM, Miller LL, Gauvin CA, et al. Population prevalence of Tourette syndrome: a systematic review and meta-analysis. Mov Disord. 2015 Feb;30(2):221-8.
http://www.ncbi.nlm.nih.gov/pubmed/25487709?tool=bestpractice.com
Tourette's syndrome in the US is diagnosed more commonly in non-Hispanic white young people than in Hispanic and non-Hispanic black young people.[10]Bitsko RH, Holbrook JR, Visser SN, et al. A national profile of Tourette syndrome, 2011-2012. J Dev Behav Pediatr. 2014 Jun;35(5):317-22.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4484726
http://www.ncbi.nlm.nih.gov/pubmed/24906033?tool=bestpractice.com
[11]Centers for Disease Control and Prevention (CDC). Prevalence of diagnosed Tourette syndrome in persons aged 6-17 years – United States, 2007. MMWR Morb Mortal Wkly Rep. 2009 Jun 5;58(21):581-5.
http://www.cdc.gov/mmwr/PDF/wk/mm5821.pdf
http://www.ncbi.nlm.nih.gov/pubmed/19498335?tool=bestpractice.com