Tic Disorders Not Protective Against Risk of Developing Tardive Dyskinesia

Patients with tic disorders may be at a higher risk of developing tardive dyskinesia, according to study findings presented at the International Congress of Parkinson’s Disease and Movement Disorders (MDS) Virtual Congress 2021, held from September 17 to 22, 2021.

Previous research assessing the side effects of tic disorders showed that this condition may decrease the risk of developing tardive dyskinesia; however, further analyses may be required to interpret these findings.

The objective of the current study was to compare the rates of tardive dyskinesia in patients with tic disorders without comorbid major psychoses, patients with major psychoses without comorbid tic disorders, and patients with comorbid tic disorders and major psychoses to determine whether tic disorders have a protective effect against tardive dyskinesia.

Study authors evaluated data from patients with major psychosis and tic disorders who were aged between 7 and 79 years when they received their first antipsychotic medication at the Mayo Clinic in Minnesota.

Patients were matched 1:3 based on type of antipsychotic, sex and age at prescription for antipsychotic. Researchers compared the groups using sequential models and Fisher’s exact test.

Of the 121 patients with tic disorders without major psychoses, none had tardive dyskinesia. Three of the 25 patients (12%) with both major psychoses and tic disorders had tardive dyskinesia, and 171 of the 4886 patients (3.5%) with major psychoses and without tic disorders had tardive dyskinesia. The risk of developing tardive dyskinesia was higher in patients with major psychoses without tic disorders compared with those with tic disorders without major psychoses (Fisher’s exact P =.04).

After adjusting for matching, the researchers observed no significant difference between patients with tic disorders without psychoses and patients without tic disorders with psychoses (0% vs 2.7%, respectively; Fisher’s exact P =.12). Patients with both tic disorders and major psychoses were more likely to have tardive dyskinesia compared with patients without tic disorders with major psychoses (odds ratio [OR], 3.8; 95% CI, 1.1-12.7 P =.03).

The link was strengthened after the researchers adjusted for sex and age at first antipsychotic exposure (OR, 5.0; 95% CI, 1.4-18.4 P =.01).

Study limitations included the inability to evaluate the impact of cumulative exposure to antipsychotics.

“Contrary to the largest available study currently available on this topic (Müller-Vahl and Krueger 2011), our results do not support the notion that patients with tic disorders are protected against developing tardive dyskinesia,” the researchers concluded. “To the contrary, intra-group comparison of patients with psychoses suggest that patients with tic disorders may even be at elevated risk of developing this side effect.”

Reference

Markota M, Coombes BJ, Duque L, et al. Risk of tardive dyskinesia in patients with tic disorders: preliminary results. Presented at: MDS Virtual Congress 2021; September 17-22, 2021. Poster 87.