Association between Tourette syndrome and comorbidities in Japan

The purpose of this study was (1) to document cases of Tourette syndrome (TS) with comorbidities such as obsessive–compulsive symptoms (OCS) and hyperkinetic disorder (HD), and (2) to examine differences in clinical characteristics between TS patients with OCS and HD and those without these comorbidities. The subjects in the study were 88 Japanese TS patients (67 males and 21 females; mean age: 15.2 years) who were treated by 31 clinicians including psychiatrists and pediatricians. Data on tic symptoms, comorbidities and severity were scrutinized. OCS were present in 42.0% of the subjects, while HD accounted for 28.4%. In the TS + OCS and/or HD group, coprophenomana, impulsiveness/aggression, school refusal, self-injurious behaviors (SIB), and clumsiness were significantly more frequent than in the TS-only group. Also, tic symptoms and impairment during the worst period was significantly severer in the TS + OCS and/or HD than in the TS-only group. When the age-matched TS + all OCS group (i.e., the young TS + OCS and TS + OCS + HD group) was compared with the TS-only group, it was found that the rates of impulsiveness/aggression, school refusal and SIB were significantly higher and the degree of global severity was significantly more intense in the young TS + all OCS group than in the TS-only group. The impact to clinical characteristics of TS from OCS was suggested to be slightly greater than that from HD. There was little ethnic difference in TS pathogenesis in terms of the impact of comorbidities. Further investigation is required to gain deeper insights into the relationships between TS, OCD or OCS and HD.