Physical frailty as an important indicator of accelerated biological aging in serious mental illnesses

The paradox of aging, that is, improvedmental wellbeing despite diminished physical and cognitive capacities, is particularly evident in those aging with mental illness (Jeste et al., 2011). For many older adults, psychiatric symptoms are not the primary cause of impairment in function and quality of life, and efforts to address accelerated biological aging in mental illnesses are critical for geriatric psychiatry care. Frailty has recently been proposed for psychiatry as a clinical measure of biological age (Bersani et al., 2020). Frailty is a multidimensional construct that broadly refers to a state of increased vulnerability to stressors and can be described along a continuum of functional capacity, from robust at one end to experiencing disability in basic activities of daily living at the other (Dent et al., 2019). The two most common constructs used to assess frailty are the physical phenotype, originally characterized by Fried et al. (2001), that includes assessing five items—unintentional weight loss, exhaustion, weakness, slow walking speed, and low levels of physical activity; and the deficit accumulation model or Frailty Index, originally proposed by Rockwood et al. (1999), that characterizes frailty on the basis of an accumulation of health conditions and deficits. Frailty is a leading contributor to functional decline and early mortality in the general aging population. However, at a prevalence of roughly 10-11% of adults over 65 years (Collard et al., 2012), frailty is not an obligatory consequence of aging and many individuals may continue to be robust into old age. While frailty is an area of current focus in geriatric medicine, its etiology is still subject to debate, and it is less well recognized in geriatric psychiatry. In this issue of IPG, Aprahamian et al. (2020) assessed physical frailty of geriatric psychiatry inpatients aged 65+ years using the FRAIL scale (an approximation of the physical phenotype) and the Frailty Index. They found that 55.3% of the sample was frail according to the physical phenotype and 83.6% according to the Frailty Index. These numbers are striking compared to the general aging population. There are several reasons why frailty may be disproportionally represented in older adults aging with mental illness. Long-term risk factors for frailty include overweight/obesity, physical inactivity, cardiovascular risk, poor self-rated health, and alcohol use (Dent et al., 2019)—risk factors that are known to commonly occur in those with mental illness. Somatic comorbidities associated with these poor lifestyle behaviors are high in older adults with mental illnesses and are responsible for a large mortality gap compared to the general aging population. Though frailty and multimorbidity are mutually inclusive, they are considered separate constructs, with the proportion of communitydwelling older adults presenting both conditions around 6%, and approximately 42% of those with multimorbidity still considered “robust” (Vetrano et al., 2019). Thus, it is unlikely that frailty is purely the result of the high multimorbidity in those aging with mental illness. Frailty prevalence is also elevated in populations with less education, low socioeconomic position, and ethnic minority groups, which aligns with the well-known socioeconomic disparity associated with mental illnesses. Many of these factors relate to the living environment, which is now being recognized as a determinant of the Healthspan. Byrne et al. (2013) found that the concentration of persons with serious mental illness within a neighborhood’s adult population was associated with higher levels of physical and structural inadequacy, crime, drugrelated activity, social instability, and social isolation. Such factorsmay reduce the life space and limit community participation and social interactions. In addition, behavioral phenomena commonly associated with mental illnesses, such as physical anergia, avolition, and apathy, further impact the activities in which an individual chooses to participate. While these behavioral symptoms share overlap with some diagnostic criteria of the DSM-5, this does not necessarily invalidate them as risk factors for frailty. Apathy has been independently associated with the development of frailty in community-dwelling older adults (Ayers et al., 2017), and exhaustion is often one of the initial manifestations of frailty criteria. It is plausible that lifestyles characterized by these environmental constraints and behavioral antecedents result in phenotypic rigidity versus adaptability of those with mental illnesses, which in turn predisposes these individuals to becoming frail. Other groups in addition to Aprahamian et al. (2020) have demonstrated the importance of International Psychogeriatrics (2022), 34:11, 955–957 © International Psychogeriatric Association 2021