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Why people with severe mental illness are more likely to be hospitalised with infections

by Craig Perryman | 6 Jul 2026

At a glance

Around one in eight people with severe mental illness in this study were hospitalised for an infection, with significantly higher mortality among those affected
Risk is not the same for everyone and is shaped by a combination of physical health, daily functioning, substance use, and healthcare access
Many risk factors are linked to how care is delivered, suggesting opportunities for prevention through better, more personalised support

A clear and serious health gap

The study confirms what we already know: people living with severe mental illness are more likely to experience serious infections that require hospital care. Around one in eight people in the study were hospitalised for an infection during the follow-up period.

Respiratory infections were the most common, followed by urinary and skin infections. Importantly, people who had an infection-related hospitalisation were far more likely to die during the study period than those who were not hospitalised.

This reinforces a wider message. Physical and mental health are closely connected, and people living with mental illness often face poorer outcomes across both.

It’s not one risk, but many

What makes this MQ-funded research particularly valuable is that it looks beyond overall risk to understand why some people are more vulnerable than others.

The researchers found that several factors were linked to a higher likelihood of hospitalisation for infections, including:

Older age at diagnosis
Physical health problems and disability
Dementia and substance use
Difficulties with daily living
Greater use of emergency and inpatient healthcare
Certain treatments, including clozapine

Crucially, these factors do not act in isolation. Instead, they combine in different ways for different people.

The study identified distinct patterns in the data, suggesting that vulnerability is not the same for everyone. For example, one group included older people with poorer physical health and higher levels of disability, who experienced particularly high rates of infection-related hospitalisation. Another group was younger but had different patterns of healthcare use and needs.

The role of healthcare systems

Many of the factors identified in the study point towards how care is delivered and accessed, rather than being inevitable outcomes of illness.

For example, higher rates of emergency hospital admissions for conditions that should usually be managed in the community may signal gaps in ongoing care. Difficulties in managing physical health conditions or accessing timely support can increase the likelihood that problems escalate.

This highlights an important opportunity. Improving access to proactive, joined-up care could help reduce the risk of serious infections.

What this means for people and services

A key message from the research is that poor infection outcomes are not unavoidable. Instead, they are shaped by a range of modifiable factors, from how services are organised to how people are supported in managing their health.

The study points to several areas where improvements could make a difference:

Better support for physical health alongside mental health care
Earlier and more consistent follow-up in the community
Improved access to preventative measures such as vaccination
Tailored approaches for people with more complex needs

The importance of lived experience

One of the strengths of this research is the involvement of people with lived experience throughout the study. Their input helped shape the research questions and interpret the findings.

From this perspective, the results highlight well-known challenges. These include difficulties accessing primary care, not always being taken seriously when reporting physical symptoms, and struggling to manage treatment during periods of poor mental health.

The findings reinforce that concerns about physical health are valid and should be taken seriously. They also support calls for more respectful, responsive, and proactive care.

Looking ahead

This study, led by MQ Fellow Dr Amy Ronaldson, adds to growing evidence that improving physical health outcomes for people living with severe mental illness requires a whole-system approach.

Understanding patterns of risk is a crucial step. The next is to act on that knowledge, by developing services that are more personalised, more accessible, and better connected.

With the right support, many of the risks identified in this research can be reduced. That means fewer hospitalisations, better health outcomes, and ultimately, longer and healthier lives.

MQ is currently accepting expressions of interest for our 2026 Schizophrenia Fellowships. If you are a researcher exploring schizophrenia, then find out more here.