Tardive dyskinesia: determinants of temporal dynamics of its emergence.

BACKGROUND: The second generation antipsychotics (SGA) is considered to have contributed to the decrease of the risk of TD in comparison with the first generation antipsychotics (FGA). Using the multiple regression analysis, we compared the predictive strength of the FGA/SGA distinction with the predictive strength of the duration of treatment, patients' age and sex. The difference between sedative (sed) and incisive (inc) antipsychotics was added as the fifth predictor.

METHOD: A cohort of patients treated with antipsychotic drugs for less than 5 years and who were free from TD was followed for one year and examined regularly by the abnormal involuntary motor scale (AIMS).

RESULTS: From a sample of 98 patients, 6 patients developed TD after six months. The duration of treatment, age and sex of the patients were the main determinants of its emergence. The drugs used did not play a statistically significant role. After one year, 15 patients developed TD. Age and sex lost their statistically provable influence on its emergence. The difference between the treatment with sedative or incisive antipsychotics became the variable with the highest statistical significance. The relationship of the risk of TD to the FGA/SGA distinction was not statistically significant. 14.4% of the variability in the increase of the risk of TD during the second half of the one year observational period could be explained by the predictors. The stepwise regression showed that both, SG/FG and sed/inc distinction remained statistically significant.