Socioeconomic and clinical determinants of mental health service use: a population-based cohort study exploring frailty as a potential mediator.

This population-based cohort study aimed at evaluating the association between clinical and socio-demographic characteristics and recorded access to mental health care. We included over 750,000 adult residents in central Italy, followed from January 2020 to December 2022. Multivariable logistic models were run separately for gender, and for prevalence and incidence of access; the analysis specifically assessed the interaction and the potential modifying role of clinical frailty regarding foreign country of birth and residency in highly deprived areas, through a four-way decomposition framework. A higher prevalence and incidence of mental care access were observed among women, elderly 65+, Italian-born, residents in deprived areas, individuals living alone or with one other person, clinically frail, and Emergency Room frequent users for non-psychiatric diagnosis. The simultaneous presence of clinical frailty and high deprivation resulted in a significant threefold increase in prevalence for female patients (Odds Ratio, OR = 3.02; 95%CI 2.89-3.15). Immigrants have lower access to mental health services, but the interaction between frailty and foreign country of birth reversed the effect (prevalence: OR males = 1.56; 95%CI 1.32-1.84, OR females = 2.39; 95%CI 2.14-2.66; incidence, significant for males only: OR = 1.79; 95%CI 1.42-2.28). The observed confluence of poor health and social vulnerability affecting the recorded access to mental health services suggests the need for integrated health and social care approaches for preventing mental health disorders, while improving equity in the enrollment process.