Background Frailty is increasingly being considered as multidimensional and can encompass physical, cognitive, psychological, and social frailty domains. However, while the physical and cognitive domains of frailty are established within the evidence base, there remains a lack of consensus over the psychological and social aspects of frailty. Therefore, the aims of this scoping review were to establish the extent of focus on psychological and social frailty within the frailty literature; how these domains are conceptualised/operationalised; and how they relate to physical and cognitive frailty.

Methods Using a focused search strategy to limit the scope to psychological and social frailty, one reviewer (MMcK) searched seven databases (CINAHL, EMBASE, MEDLINE, PubMED, Scopus, Web of Science, PsychINFO). Results were screened independently by two reviewers (MMcK, SC), without limits on date or geographic location of publication. Publications were considered eligible if they were focused on the specific domains of this review in community-dwelling individuals aged 50 years and over. Data was extracted using a piloted form and collated into descriptive and narrative synthesis.

Results Of 303 papers screened, 38 were included for full review. The majority of these were exclusively focused on social frailty (53%), whereas only 8% were focused on psychological frailty alone. The remaining 39% considered both domains along with other aspects of multidimensional frailty. Only one study per year was identified prior to 2014, with an exponential increase after this point highlighting the novelty of this area. Operationalisation of psychological frailty included the co-occurrence of physical frailty and low mood, depression, loneliness, and cognitive impairment. Social frailty was operationalised using a range of social concepts, including but not limited to loneliness, social support, participation, role, relationships, and networks. There was an interchangeability in definitions and measurements between frailty domains, with loneliness being utilised in measuring both psychological and social frailty, and in some cases cognitive frailty was conceptualised as psychological frailty. Both psychological and social frailty were consistently highly associated with adverse outcomes, including disability and mortality. However, the publications differed significantly on whether these associations were independent of or in addition to physical frailty.

Conclusion This review found that amongst the literature on psychological and social frailty there was little consensus on measurement, definitions, or the relationship between different frailty domains. What was evident, however, were the robust associations between negative outcomes and psychological and social frailty, which suggests that they should be afforded the same weight as the physical and cognitive frailty domains.