Somatic and psychotropic polypharmacy in people with long-term mental health problems

This project is looking at the effects of polypharmacy (taking multiple medications at the same time) in people living with multiple physical and mental health problems.

Multimorbidity in mental health and between mental and physical health is relatively under-researched. Both long-term physical and psychiatric disorders are associated with poverty and social inequality, but the relationship is not well understood. Prescribing is complicated by comorbidity some medications may have detrimental effects on mental or physical health, or drug combinations may have detrimental effects.

Depression and type 2 diabetes (T2D) are common and serious conditions each can exacerbate the other. Antidepressants are a common treatment for depression, but have side effects that may exacerbate T2D. We used primary care electronic health record data to investigate, in people with depression and T2D, associations between polypharmacy and antidepressant prescribing, and antidepressants and long-term physical health outcomes.

In some instances, de-prescribing medication may be the optimal approach, but evidence for this is unlikely to come from randomised controlled trials and needs innovative approaches using data from large electronic health record databases.

We found people prescribed more concurrent medications are less likely to stop antidepressant treatment before recommended duration, and more likely to restart antidepressant treatment after stopping. Antidepressant prescribing associated with 278% increase in rate of starting insulin and 176% increase in rate of all-cause mortality. Rather than a causal relationship, antidepressants likely to be markers of worse depression severity, associated with worse long-term physical health outcomes.

Findings, relevant for primary care, have been published, and show antidepressant prescribing is a marker for increased health needs in people with depression and T2D, who need close monitoring and enhanced collaborative care.

NIHR UCLH Biomedical Research Centre

Camden and Islington NHS Foundation Trust

University of Hong Kong

UCL