A systematic review of the prevalence of depression, anxiety, and apathy in frontotemporal dementia, atypical and young-onset Alzheimer’s disease, and inherited dementia

Abstract

Depression, anxiety, and apathy are the most commonly reported neuropsychiatric symptoms (NPS) in Alzheimer’s disease (AD). Understanding their prevalence in rarer dementias such as frontotemporal dementia (FTD), primary progressive aphasia (PPA), posterior cortical atrophy (PCA), young-onset AD (YOAD), and inherited dementias has implications for both clinical practice and research. In this study, we aimed to examine the current state of knowledge of the prevalence of these three NPS in less prevalent dementias. We conducted a systematic review based on searches of EMBASE, PsycINFO, and PubMed up to September 2019. 47 articles meeting inclusion criteria were identified. Depression, anxiety, and apathy were commonly reported across the phenotypes studied but their prevalence showed large variation between studies. Apathy showed the highest reported frequency in FTD (50–100% across studies), behavioral variant frontotemporal dementia (bvFTD) (73–100%), and YOAD (44–100%). Anxiety was frequently reported in FTD (0–100%) and bvFTD (19–63%). Depression showed the highest prevalence in FTD (7–69%) and YOAD (11–55%). Among the three variants of PPA, sv-PPA is the one most investigated (seven articles). Three or fewer articles were identified examining NPS in the remaining PPA variants, PCA, familial AD, and familial FTD. Inconsistency in the tools used to measure symptoms and small sample sizes were common methodological limitations. Future studies should consider the inclusion of larger sample sizes (e.g. through multicenter collaborations) and the use of harmonized protocols that include the combination of caregiver and patient-derived measures and symptom-specific questionnaires. More research is needed on the phenotype-specific barriers and facilitators for people living with dementia to successfully engage in self-reports of NPS.