# Inappropriate trusting behaviour in dementia

## TL;DR

People with certain types of dementia, like FTD and svPPA, are more likely to show inappropriate trusting behavior, which can lead to risks in their daily lives.

## Contribution

This study identifies specific dementia subtypes and clinical predictors associated with inappropriate trusting behavior.

## Key findings

- Inappropriate trusting was more common in svPPA and bvFTD compared to AD and nfvPPA.
- Apathy predicted inappropriate trusting in svPPA, while disinhibition and pain responsiveness predicted it in bvFTD.
- Lower MMSE and RSMS scores in AD were linked to inappropriate trusting behavior.

## Abstract

Inappropriate trusting behaviour may have significant social, financial and other consequences for people living with dementia. However, its clinical associations and predictors have not been clarified. Here we addressed this issue in canonical syndromes of frontotemporal dementia (FTD) and Alzheimer’s disease (AD).

In 34 patients with AD and 73 with FTD (27 behavioural variant (bv)FTD, 22 semantic variant primary progressive aphasia (svPPA), 24 nonfluent/agrammatic variant (nfv)PPA) we recorded inappropriate trusting and other abnormal socio-emotional behaviours using a semi-structured caregiver survey. Patients were comprehensively characterised using a general cognitive assessment and the Revised Self-Monitoring Scale (RSMS; an informant index of socioemotional awareness).

Inappropriate trusting was more frequent in svPPA (55%) and bvFTD (44%) than nfvPPA (17%) or AD (24%). After adjusting for age, sex, education and Mini-Mental State Examination (MMSE) score, inappropriate trusting was significantly more likely in svPPA (odds ratio 3.61; 95% confidence interval 1.41–8.75) and bvFTD (3.01, 1.23–6.65) than AD. Significant predictors of inappropriate trusting comprised apathy in svPPA, disinhibition and altered pain responsiveness in bvFTD, and lower MMSE and RSMS (self-presentation) scores in AD.

Dementia syndromes vary in prevalence and predictors of abnormal trusting behaviour, with implications for clinical counselling and safeguarding.