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Dementia Patients on Psychotropic Medications at High Risk For Collisions

October 8, 2008

Older drivers with dementia who are prescribed psychotropic medication and/or exhibit psychiatric symptoms should be evaluated for road safety, says new research from the Institute of Clinical Evaluative Sciences (ICES), Ontario Ministries of Health and Transportation and Sunnybrook Health Sciences Centre.

"Patients on psychotropic medications - antipsychotics, benzodiazepines or antidepressants - were at a significantly greater risk of a motor vehicle collision (MVC) by approximately 50 percent," says Dr. Mark Rapoport, lead investigator of the study, psychiatrist at Sunnybrook Health Sciences Centre, and Assistant Professor in the Department of Psychiatry at University of Toronto.  "Although behavioural disturbances sometimes predict driving cessation in dementia, there are many of these patients who do not cease driving and may be at a distinctly higher risk."

The study showed that antipsychotic medications were associated with the highest risk of a collision, benzodiazepines were associated with a modestly greater risk than placebo, and the risk with antidepressants was intermediate, with newer antidepressants paradoxically posing a higher risk than the older ones.

"We've known for a long time that dementia poses a serious risk to road safety, and this is a condition in which depression, delusions and agitation are quite common.  The study suggests a marked increase in this risk associated with these behavioral and psychological symptoms," says Dr. Rapoport, who is also a team member on the project CanDRIVE - Keeping Safe Older Drivers Driving.

"The greater risk of a motor vehicle collision may reflect the underlying indication for the prescriptions rather than the pharmacological properties of the drugs themselves," adds Dr. Nathan Herrmann, co-investigator of the study, geriatric psychiatrist at Sunnybrook and a Professor at University of Toronto.

Study authors included those from Sunnybrook, The Ottawa Hospital, Baycrest Centre for Geriatric Care, and ICES. "The collaborative and confidential sharing of data from the Ontario Ministries of Health and Transportation with ICES was an important innovation implemented for this study, paving the way for potential future research on road risks associated with health conditions," adds Rapoport. The study was funded by the Physicians Services Inc. Foundation.

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