The criteria for testamentary capacity developed from the case of Banks v Goodfellow (1870)[i] include: …that no disorder of the mind shall poison his affections, pervert his sense of right, or prevent the exercise of his natural faculties – that no insane delusion shall influence his will in disposing of his property and bring about a disposal of it which, if the mind had been sound, would not have been made.
But what exactly is an insane delusion and what causes a person, particularly an older person, to suffer insane delusions? The legal definition of delusion was elaborated by Sedgewick J. in Skinner v. Farquharson (1902)[ii] “… Delusion is insanity where one persistently believes supposed facts (which have no real existence except in his perverted imagination) against all evidence in probability and conducts himself however logically upon the assumption of their existence.”
In more modern times, Justice Cullity’s decision in Banton v. Banton (1998)[iii] provides clarity on understanding the legal view on insane delusions in paragraph : “As the second of these passages indicates, “insane” delusions are not limited to beliefs that are so bizarre that their content, by itself, evidences mental disorder. Such delusions include beliefs whose extreme improbability is apparent only when the surrounding facts are known. These are obviously the more difficult cases. Delusions with respect to the behaviour and attitudes of the deceased’s relatives are relatively common in the reported cases and they often fall into this category. In all cases where delusions of this kind are alleged to exist there will be a question whether the belief should be characterized merely as quite unreasonable, on the one hand, or as something that, in the particular circumstances, no one “in their senses” could believe: Macdonell, Sheard and Hull on Probate Practice (4th ed., by Rodney Hull, Q.C., and Ian Hull, 1996) at pp. 33-34. …”
From the clinical psychiatric perspective, the recently released DSM-5[iv] defines delusions (in Schizophrenia Spectrum and Other Psychotic Disorders) as the following: Delusions are fixed beliefs that are not amenable to change in light of conflicting evidence. Delusions are deemed bizarre if they are clearly implausible and not understandable to same-culture peers and do not derive from ordinary life experiences. The distinction between a delusion and a strongly held or over-valued idea is sometimes difficult to make and depends in part on the degree of conviction with which the belief is held despite clear or reasonable contradictory evidence regarding its legitimacy.
In regards to testamentary capacity, the distinction between immoral yet permissible overvalued ideas and delusional beliefs that nullify the will validity can be difficult to define. Delusions and non-delusional beliefs are best conceptualised as a spectrum rather than a dichotomous phenomenon. A person may hold over-valued ideas which are sustained beliefs maintained with less than delusional intensity but potentially capable of poisoning affections if pervasive and persistent. While delusions are usually ‘false’ beliefs (and can often be diagnosed as such by their very implausibility), they are not invariably so, and thus the distinction of being false was dropped from DSM-5. Rather, their hallmark is that they are not arrived at through normal processes of logical thinking, are held on inadequate grounds, are resistant to conflicting evidence, and most importantly are not bendable to reason.[v] That is they are held with absolute 100% probability without even 1% of doubt. Delusions may arise in many forms of mental illness in seniors, most commonly in dementia, including the milder less obvious stage, as well as in delirium, depression, mania and schizophrenia.
However delusions may also occur in people without a recognized major mental illness[vi] [vii] making it quite challenging to evaluate the testator with seemingly unnatural or immoral decisions such as to disinherit a natural beneficiary. Such cases are a cause for consideration for an expert clinical psychiatric contemporaneous evaluation of testamentary capacity regarding the reasoning behind any such unnatural or immoral decisions.
Nevertheless, an expert evaluation may still be limited because of the testator who desires secrecy of the contents of the will until his passing. Clinical assessments in geriatric psychiatry typically require corroborative third-party evidence to provide a thorough and complete assessment. Particularly when there are changes made to bequests to natural beneficiaries, a complete understanding of the reasoning behind such changes may not be apparent without corroborative information from family members and/or beneficiaries, including especially those who are subject to the unnatural decisions and not just the favoured beneficiary who most likely will be the one to accompany the testator to the assessment – but who actually may be the one who has precipitated and/or perpetuated the delusions in the first place in keeping with being the perpetrator of unrecognized undue influence!
[i] Banks v Goodfellow (1870) L.R. 5 QB 549
[ii] Skinner v. Farquharson (1902), 32 S.C.R. 58 (S.C.C.)
[iii] Banton v. Banton, 1998 CanLII 14926 (ON SC),
[iv]. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA, American Psychiatric Association, 2013. Web. [access date: 1 June 2013]. dsm.psychiatryonline.org.
[v] Bortolotti, L. (2010). Delusions and other irrational beliefs. Oxford University Press.
[vi]Johns, L. C., & Van Os, J. (2001). The continuity of psychotic experiences in the general population. Clinical psychology review, 21(8), 1125-1141.
[vii] Van Os, J., Linscott, R. J., Myin-Germeys, I., Delespaul, P., & Krabbendam, L. (2009). A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness–persistence–impairment model of psychotic disorder. Psychological medicine, 39(02), 179-195.