Background: As people live longer, there is increasing potential for mental disorders to interfere with testamentary distribution and render older people more vulnerable to "undue influence" when they are making a will. Accordingly, clinicians dealing with the mental disorders of older people will be called upon increasingly to advise the courts about a person's vulnerability to undue influence.
Method: A Subcommittee of the IPA Task Force on Testamentary Capacity and Undue Influence undertook to establish consensus on the definition of undue influence and the provision of guidelines for expert assessment of risk factors for undue influence.
Results: International jurisdictions differ in their approach to the notion of undue influence. Despite differences in legal systems, from a clinical perspective, the subcommittee identified some common "red flags" which might alert the expert to risk of undue influence. These include: (i) social or environmental risk factors such as dependency, isolation, family conflict and recent bereavement; (ii) psychological and physical risk factors such as physical disability, deathbed wills, sexual bargaining, personality disorders, substance abuse and mental disorders including dementia, delirium, mood and paranoid disorders; and (iii) legal risk factors such as unnatural provisions in a will, or provisions not in keeping with previous wishes of the person making the will, and the instigation or procurement of a will by a beneficiary.
Conclusion: This review provides some guidance for experts who are requested by the courts to provide an opinion on the risk of undue influence. Whilst international jurisdictions require different thresholds of proof for a finding of undue influence, there is good international consensus on the clinical indicators for the concept.