Addressing the Slippery Slope Argument: Trends in Euthanasia Among Patients with Psychiatric Disorders and Dementia in Belgium, 2002-2023

BackgroundAssisted suicide of patients with psychiatric disorders or dementia have increased in countries like Belgium, the Netherlands, and Canada and are often mentioned to argue against euthanasia regulations, suggesting they lead to a slippery slope. We examine changes in euthanasia cases for patients with these conditions in Belgium. Data and methosWe use data on all cases of euthanasia reported to the Federal Commission for the Control and Evaluation of Euthanasia (FCCEE) from 2002 to 2023. Psychiatric disorders (N=427) and dementia (N=310) represent 1.27% and 0.92% of all cases, respectively. Using time-series Poisson regression, we model trends by first examining interactions between euthanasia reasons and year, then extending to three-way interactions with gender and region. We replicate the analyses with an offset to account for demographic changes. ResultsEuthanasia for psychiatric disorders and dementia showed distinct trends over time. Euthanasia for psychiatric disorders followed trends similar to the other types of euthanasia, while euthanasia for dementia showed a slight over-increase. Demographic change explains part of the increase in euthanasia for dementia and other reasons but not psychiatric disorders. While euthanasia rates for psychiatric disorders were initially higher for women, the trend for men is catching up over time. Regional trends indicate higher overall euthanasia rates in the Dutch-speaking population but with faster increases in the French-speaking population. DiscussionThe Belgian experience demonstrates that assisted dying laws can include non-terminal psychiatric conditions with appropriate safeguards and without evidence of significant misuse, addressing concerns about the slippery slope argument.