The following article is part of the conference coverage of the virtual annual meeting of the International Congress on Parkinson’s and Movement Disorders (MDS). Neurology Advisor staff will share the latest news related to research from leading neurology experts. Look back for the latest news from the MDS 2021 Annual Virtual Meeting.
Patients with tic disorders may have a higher risk of developing tardive dyskinesia, according to study results presented at the 2021 virtual congress of the International Congress on Parkinson’s and Movement Disorders (MDS) from September 17-22, 2021.
Previous research looking at the side effects of tic disorder showed that this condition can reduce the risk of tardive dyskinesia; however, further analysis may be required to interpret these results.
The aim of the current study was to compare the incidence of tardive dyskinesia in patients with tic disorders without comorbid severe psychosis, patients with severe psychosis without comorbid tic disorder, and patients with comorbid tic disorder and severe psychosis to determine whether tic -Disorders have a protective effect against tardive dyskinesia.
The study authors evaluated data from patients with severe psychosis and tic disorders who were between 7 and 79 years old when they received their first antipsychotic medication at the Mayo Clinic in Minnesota.
Patients were assigned in a 1: 3 ratio based on the type of antipsychotic, gender, and age at which the antipsychotic was prescribed. The researchers compared the groups using sequential models and Fisher’s exact test.
None of the 121 patients with tic disorders without severe psychosis had tardive dyskinesia. Three of the 25 patients (12%) with severe psychoses and tic disorders had tardive dyskinesia and 171 of the 4886 patients (3.5%) with severe psychoses and without tic disorders had tardive dyskinesia. The risk of developing tardive dyskinesia was higher in patients with severe psychoses without tic disorders than in patients with tic disorders without severe psychoses (Fisher’s exact P = .04).
After adjusting for the matching, the researchers observed no significant difference between patients with tic disorders without psychoses and patients without tic disorders with psychoses (0% and 2.7%, respectively; Fisher’s exact P = 0.12). Patients with tic disorders and severe psychoses had tardive dyskinesia more often than patients without tic disorders with severe psychoses (odds ratio [OR], 3.8; 95% Cl, 1.1-12.7 P = 0.03).
The association was reinforced after the researchers adjusted sex and age at the first antipsychotic exposure (OR, 5.0; 95% CI, 1.4-18.4 P = 0.01).
One of the limitations of the study was the inability to assess the effects of cumulative exposure to antipsychotics.
“In contrast to the currently largest study available on this topic (Müller-Vahl and Krueger 2011), our results do not support the idea that patients with tic disorders are protected from the development of tardive dyskinesias,” the researchers concluded. “On the contrary, the group-internal comparison of patients with psychoses suggests that patients with tic disorders actually have an increased risk of developing this side effect.”
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; 17.-22. September 2021. Poster 87.