Changes in negative symptoms and the risk of tardive dyskinesia: a longitudinal study

Objective: To examine whether the development of tardive dyskinesia (TD) is accompanied by a parallel process of worsening negative symptoms in a long itudinal study. Method: A sample of 708 psychotic patients were followed over a period of 2 years, using the Abnormal Involuntary Movement Scale and the Scale for the Assessment of Negative Symptoms (SANS). Results: Of 361 individuals with no prior evidence of dyskinesia, 46 (13%) developed TD by year 2, Independent of the effects of male sex (odds Patio (OR) = 2.18, 95% confidence interval: 1.00-4.74), age (OR per quartile grou p = 1.39, 95% CI: 1.01-1.90), duration of exposure to antipsychotic medicat ion (OR = 2.35 per 8 months, 95% CI: 1.17-4.72) and average SANS score (OR per quartile group = 1,38, 95% CI: 0,99-1.93), worsening of negative sympto ms over the 2 previous years was associated with TD onset (OR per quartile group = 1.46, 95% CI: 1.07-2.00). Conclusion: The development of TD is linked, independent of the effect of a ntipsychotics and older age, to an illness-related pathological process, ch aracterized by worsening negative symptoms.