DURATION OF NEUROLEPTIC TREATMENT AND PREVALENCE OF TARDIVE-DYSKINESIA IN LATE-LIFE

Background: Although increasing age is the most consistently cited ris k factor for the development of tardive dyskinesia for patients in the second to sixth decades of life, this relationship may not hold withi n geriatric populations.Methods: Consecutively admitted geropsychiatri c inpatients were examined with the Abnormal Involuntary Movement Scal e within 72 hours of admission; comprehensive demographic, diagnostic, and psychometric data were also obtained. Results: Seventy-four (19.2 %) of 386 patients received diagnoses of dyskinesia. Lifetime duration of neuroleptic use was strongly correlated with dyskinesia rates. Aft er accounting for the effect of lifetime duration of neuroleptic use i n a stepwise logistic regression, only associations with Global Assess ment Scale score and presence of dental problems remained statisticall y significant. In comparison with the duration of neuroleptic use, how ever, the contribution of these factors mas minor. Sixteen percent of patients with less than 3 months of neuroleptic use, 29% with 3 to 12 months of neuroleptic use, 30% with 1 to 10 years of neuroleptic use, and 41% with more than 10 years of neuroleptic use had dyskinesia. Com pared with patients with no history of neuroleptic treatment, the rela tive risks for these durations of neuroleptic use were 1.62 (95% confi dence limits [CL],0.81, 3.24), 2.89 (95% CL, 1.50, 5.55), 3.08 (95% CL , 1.66, 5.70), and 4.11 (95% CL, 2.12, 7.96), respectively. Conclusion s: Within elderly populations, duration of exposure to neuroleptics is the strongest predictor of risk for tardive dyskinesia, and this risk increases rapidly within the first year of total lifetime neuroleptic use.