Polypharmacy, severe mental illness and impaired mobility in multiple long-term health conditions: a scoping review

Introduction: Multiple long-term health conditions and multimorbidity (MLTC-M) disproportionally impact older people. Literature highlights associations between polypharmacy, mobility issues, and severe mental illness and MLTC-M. Co-existence of polypharmacy, mobility issues, and severe mental illness with MLTC-M may impact on older people’s health outcomes, however the extent to which these have been explored is unclear.

Aim This scoping review aimed to describe the evidence regarding interventions and outcomes associated with the intersection of polypharmacy, mobility issues, and severe mental illness with MLTC-M.

Methods: Medline, Embase, Scopus, Psychinfo and CINAHL were searched for evidence sources that discuss at least two of polypharmacy, mobility issues, and severe mental illness with MLTC-M. Two reviewers independently screened titles and abstracts and full texts against the inclusion and exclusion criteria. Data pertaining to people’s interventions and outcomes were extracted and synthesised narratively.

Results: 6540 studies were included in the title and abstract screening and 1237 proceeded to full text screening. Research exploring the interaction between polypharmacy, severe mental illness and mobility collectively accounts for 5% of evidence sources progressing to full text screening. Roughly a third of included papers are concerned with polypharmacy and mobility, such as higher drug burden increasing the risk of falls. Papers reporting on polypharmacy and severe mental illness also make up roughly a third, such as tardive dyskinesia and kinesia. Just under a third of papers discuss the relationship between severe
mental illness and mobility, such as high prevalence of metabolic syndrome in schizophrenia causing mobility limitations.

Conclusions: The results of the review suggest that there could be a bidirectional relationship between severe mental illness and impaired mobility, mediated by polypharmacy. Drug-drug interactions could increase the risk of mobility problems in older people with severe mental illness and increase psychiatric problems in older people with impaired mobility.