DISCUSSION Through a modified Delphi-method, 13 expert consensus-criteria for IPS in the context of PAD were identified, regarding diagnosis and treatment. Diagnostic criteria Participants considered a DSM classification necessary when determining IPS, but even more participants considered the presence of a narrative description and attention to the contextual and systemic elements necessary. These criteria are in line with clinical guidelines describing best practice in psychiatric evaluation. (Hengeveld, no date; Silverman, 2016) The criteria imply that a certain degree of individual interpretation will always be part of the decision-making process concerning IPS in the context of PAD. Further deliberation should focus on what levels of individual interpretation are justifiable. (Berghmans, Widdershoven and Widdershoven-Heerding, 2013) All participants agreed that a mandatory second opinion should be a criterion of IPS in the context of PAD. This endorses the current due diligence procedures in the Netherlands and Belgium. (Regional Euthanasia Review Committess RTE: Code of Practice, 2015; Vlaamse Vereniging voor Psychiatrie, 2017; Nederlandse Vereniging voor Psychiatrie, 2018) Furthermore, a second opinion can mitigate the risk of interpretative differences. Canadian policymakers should take this insight into account when developing the due diligence procedures for psychiatric PAD and weigh whether this is feasible in a vast and low populated country or that other solutions, such as teleconsulting are more prudent. The participants also agree that, although there must be evidence of a substantial clinical history (described in detail below), there should be limits to the number of diagnostic procedures a patient has to undergo before IPS can be established. Especially when this patient has a long history of illness and treatment. This criterion suggests that if the patient refuses certain diagnostic procedures, it does not automatically mean that IPS cannot be established. It may be justified to only demand additional diagnostic procedures, such as neuropsychological or personality testing, when there is a reasonable chance that this will lead to new treatment options. Treatment criteria The participants agree that substantial treatments have to have failed before IPS can be established. This is in line with earlier studies. (Onwuteaka-Philipsen et al., 2017; van Veen et al., 2018; van Veen, Ruissen and Widdershoven, 2020) The participants also agree that, because all reasonable treatments must be tried, the A DELPHI STUDY ON IRREMEDIABILITY | 109 6