Changes in negative symptoms and the risk of tardive dyskinesia:a longitudinal study
Abstract:Objective –To examine whether the development of tardive dyskinesia (TD) is accompanied by a parallel process of worsening negative symptoms in a longitudinal 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. 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 ratio (OR)=2.18, 95% confidence interval: 1.00–4.74), age (OR per quartile group=1.39, 95% CI: 1.01–1.90), duration of exposure to antipsychotic medication (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 symptoms 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 antipsychotics and older age, to an illness‐related pathological process, characterized by worsening negative symptoms.
Document Type: Research Article
Publication date: April 1, 2000