Culpability for offenses in frontotemporal dementia and other brain disorders

A Scoping Review of Ethical and Legal Issues in Behavioural Variant Frontotemporal Dementia

“…In recent years, there has also been both recognition and concern about the complex relationship between FTD, particularly bvFTD, and criminal behaviour. In contrast to other forms of dementia, as mentioned above, bvFTD spares memory and learning in its early stages, and instead, its most striking symptoms are impairments to moral decision-making, empathy, punishment and reward processing, and impulse control (2)(3)17). As such, this nexus of symptoms leads individuals with bvFTD, specifically in the early stages of the disease, to be at a higher risk of violating moral and legal norms; many such transgressions committed by individuals with bvFTD are criminal, with their likelihood of criminality being significantly more like than those with other forms of dementia (18).…”

“…Our review also suggests existing interest and concern about the involvement of individuals with bvFTD. Although bvFTD has been thought to raise a range of complex legal issues (17,19,21,35), results indicate that to date this literature's primary focus has been on how evidence of bvFTD is used in trial proceedings, and, to a lesser extent, issues related to determining and standards of legal insanity in cases involving bvFTD (i.e., the M'Naghten Rule). A range of different types of evidence on bvFTD, including neuroimaging data, psychiatric or neuropsychological reports, and genetic testing, have been discussed to support diagnoses of bvFTD in legal proceedings (19).…”

“…Yet, neuroimaging data appears to be by far the most prevalent way of supporting diagnoses of bvFTD in legal proceedings, with a combination of MRI, SPECT, and PET methods used to accurately and efficiently provide evidence of a diagnosis, with oftentimes little reference to other diagnostic criteria (21,35). This is surprising, given that neuroimages alone cannot be used to diagnose the disorder, with both short-and longer-term clinical tracking and third-party corroboration of behavioural changes considered imperative to an accurate diagnosis (17). Indeed, there is no clear neurological or physiological marker for FTD, with neuroimages of individuals with bvFTD often showing distinctive types and variable degrees of atrophy to affected brain regions that can differ from individual to individual (19).…”

“…Given the prevalence and role that neuroimaging evidence appears to hold in legal proceedings as tests or proof of bvFTD, those involved in the legal process, who are unlikely to be familiar with its complex methodology, should be more educated about neuroimaging in general, as well how neuroimaging evidence on bvFTD should be used to support a bvFTD diagnosis. Particularly, as neuroimaging only represents one of three criteria needed for diagnosis (17), legal decision-makers, including defense attorneys, prosecutors, and judges, should be aware of the limitations of and potential errors in using neuroimages as the sole or chief proof of bvFTD without other clinical and behavioural evidence.…”