Movement Disorders and Mortality in Severely Mentally Ill Patients: The Curacao Extrapyramidal Syndromes Study XIV

Abstract

Background and hypothesis: There is a substantial gap in life expectancy between patients with severe mental illness (SMI) and the general population and it is important to understand which factors contribute to this difference. Research suggests an association between tardive dyskinesia (TD) and mortality; however, results are inconclusive. In addition, studies investigating associations between parkinsonism or akathisia and mortality are rare. We hypothesized that TD would be a risk factor for mortality in patients with SMI.

Study design: We studied a cohort of 157 patients diagnosed predominantly with schizophrenia on the former Netherlands Antilles. TD, parkinsonism, and akathisia were assessed with rating scales on eight occasions over a period of 18 years. Twenty-four years after baseline, survival status and if applicable date of death were determined. Associations between movement disorders and survival were analyzed using Cox regression. Sex, age, antipsychotics, antidepressants and benzodiazepines at each measurement occasion were tested as covariates.

Study results: Parkinsonism was a significant risk factor with an HR of 1.02 per point on the motor subscale of the Unified Parkinson's Disease Rating Scale (range 0-56). TD and akathisia were not significantly associated with mortality.

Conclusions: Parkinsonism may be an important risk factor for mortality in SMI patients. This finding calls for more follow-up and intervention studies to confirm this finding and to explore whether treatment or prevention of parkinsonism can reduce excess mortality.

Keywords: Tardive dyskinesia; akathisia; life expectancy; parkinsonism; schizophrenia; survival.