Increased risk of dying from infectious diseases for people with serious mental disorders

People with psychotic or bipolar disorders run a significantly higher risk of hospitalisation and death from influenza, pneumonia or sepsis. This is what a new register study at Umeå University, Sweden, is showing.

“In certain age groups, the proportion of deaths due to infectious diseases was sixfold. This means that we should discuss introducing more preventive measures for these patient groups,” says Niklas Nilsson, research assistant of psychiatry at Umeå University and first author of the study

The study encompasses the entire adult population in Sweden and is based on deaths and hospitalisations for the period 2018–2019.

The researchers  compared the proportion of people with psychotic or bipolar disorders who died from or were hospitalised due to influenza or pneumonia to the rest of the population. The researchers found that the proportion of deaths from influenza or pneumonia was two-fold. In the age span of 40–59 years, the proportion of death was sixfold.

The researches also examined hospitalisation or death from the blood poisoning condition sepsis. Here, it turned out that people with psychotic or bipolar disorder were prone to considerably more hospitalisations. The proportion of death was also 60 per cent higher.

The study does not answer why people with serious mental disorders run this considerably increased risk of becoming seriously ill with or dying from infectious diseases. A possible explanation could be that people with serious mental disorders often also suffer from other underlying somatic diseases, which makes them more vulnerable. However, this does not explain the whole picture. Even when the researchers took into account risk factors such as diabetes, high blood pressure and cardiovascular disease, the proportion of deaths associated with influenza or pneumonia was still almost threefold for people with serious mental disorders compared to rest of the population.

“Based on our results, there is some evidence suggesting that serious mental disorders in itself should be classified as a strong risk factor for adverse outcomes of infectious diseases,” says Martin Maripuu, research fellow of psychiatry at Umeå University and principle investigator of the study.

Earlier in 2021, researchers in Umeå also showed that people with serious mental disorders ran a higher risk of COVID-19-associated death. After that, several countries chose to prioritise this group for vaccination.

“May be it is time to prioritise people with severe mental disorders also for vaccination against seasonal influenza and against pneumococci, a type of bacteria causing pneumonia,” says Niklas Nilsson.