Compared with the general population, patients with severe mental illness (SMI) have a shortened life expectancy by 9-25 years, explains Anna E. Willems, PhD-candidate.

“Movement disorders, such as tardive dyskinesia (TD), parkinsonism, and akathisia, are highly prevalent in patients with SMI, with up to 74% suffering from at least one movement disorder,” Willems says. “Earlier research suggests an association between movement disorders and mortality in SMI, but results were inconclusive.” She adds that studies examining the links between parkinsonism or akathisia and mortality are scarce.

 

Patients With Severe Mental Illness Followed for 18 Years

For a study published in Schizophrenia Bulletin, Willems and colleagues used data from the Curacao Extrapyramidal Syndromes Study, in which patients with SMI (N=157) were followed for 18 years. At baseline and during seven follow-ups, TD, parkinsonism, and akathisia were assessed with validated rating scales. “Since it is important to understand which factors contribute to the huge gap in life expectancy, we aimed to shed light on the potential role of movement disorders in mortality in patients with SMI,” says Dr. Willems.

Survival status and date of death, if applicable, were determined 24 years after study baseline. Cox regression was utilized to estimate the link between the three movement disorders and mortality. Gender, age, antidepressants, antipsychotics, and benzodiazepines were tested as covariates at each measurement. Cases of TD were the most prevalent, ranging between 37.6% and 61.5% at all measurements, while the incidence rates of parkinsonism and akathisia ranged from 27.4% to 40.0% and 1.3% to 12.8%, respectively.

TD Not Associated With Mortality

“Our most important finding was that while parkinsonism heightened the risk for early death, TD and akathisia did not show an association with mortality,” Willem notes.

The severity of TD is positively associated with symptom severity in schizophrenia, according to previous research, which may, as a result, be a confounding factor in the relationship between TD and survival. “Despite this association, none of the studies up to now, including the present study, controlled for psychiatric symptom severity, which poses a limitation to the findings,” the study authors wrote.

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