Secondary tics and tourettism.

Motor and phonic tics are most frequently due to Tourette syndrome, but there are many other causes of tics. We analyzed data on 155 patients with tics and co-existent disorders (101M/54F; mean age 40.5 +/- 20.2 years). Fourteen (9.0%) patients had tics associated with an insult to the basal ganglia, such as head trauma (N = 4, 2.5%), stroke (N = 2, 1.2%), encephalitis (N = 3, 1.9%) and other causes. In addition, certain drugs, toxins, and post-infectious causes were associated with tics. Rarely, peripheral injury can cause movement disorders, including tics (N = 1, 0.6%). Pervasive developmental disorders, including Asperger's syndrome (N = 13, 8.3%), mental retardation (N = 4, 2.5%), autism (N = 3, 1.9%), and Savant's syndrome (N = 1, 0.6%), also may be associated with tics, as noted in 21 of the 155 patients (13.5%). Genetic and chromosomal disorders, such as Down's syndrome 5 (3.2%), neuroacanthocytosis (N = 2, 1.2%), and Huntington's disease (N = 1, 0.6%), were associated with tics in 16 patients (10.3%). We have also examined the co-existence of tics and other movement disorders such as dystonia (N = 31, 20.0%) and essential tremor (N = 17, 10.9%). Sixteen (10.3%) patients presented psychogenic tics, and one (0.6%) psychogenic tics and dystonia; conversely, Tourette syndrome preceded the onset of psychogenic dystonia (N = 1, 0.6%), and psychogenic tremor (N = 1, 0.6%) in two patients. Finally, 12 (7.7%) patients had tics in association with non-movement related neurological disorders, such as static encephalopathy (N = 2, 1.2%) and seizures (N = 3, 1.9%). To understand the physiopathology of tics and Tourette syndrome, it is important to recognize that these may be caused or associated with other disorders.