HIV is more than twice as common in mental health service users

People who access mental health services in south London are 2.5 times more likely to have HIV than the general population in the same geographical area, according to a recent study. Researchers found that 25 in 1000 people who use mental health services had a recorded HIV diagnosis, compared with the 10 in 1000 rate in the general population.

The research found that 2.5% (4,481) of people who access secondary services at South London and Maudsley (SLaM) NHS Trust between 2007 and 2018 had a recorded HIV diagnosis in the national HIV surveillance data. Additionally, the research provided evidence of higher HIV rates for people with specific mental health diagnoses such as substance disorders (3.8%), mood disorders (2.8%) and neurotic, stress-related and psychosomatic disorders (2.7%).

This study by Dr Margaret Heslin and colleagues from King’s College London published in BMJ Open is the first-ever attempt to measure the prevalence of HIV in mental health service users in the UK. Previous international studies have highlighted poorer cardiovascular and metabolic health outcomes in people with mental ill health. Still, there is little evidence about infectious diseases apart from data on the increased risk of blood-borne viruses in people with psychosis and substance use disorders.

Between 2007 and 2018, electronic records from 181,177 people accessing services for the first time at SLaM were anonymised, compared and matched with national HIV surveillance data held by the UK Health Security Agency. This showed that 4,481 people (2.5%) had an HIV diagnosis, before, during or after their contact with SLaM, which is the main provider of secondary mental health care (services not provided in primary care) in the area.

The study used the most recent primary mental health diagnosis in people's mental health records and included a category for people without a formal mental health diagnosis. The average age of the study participants was 34 years old, 75% of participants were men and 34% were White British.

Of the 4481 people using mental health services with a recorded HIV diagnosis, 18% (784 people) had a diagnosis of substance disorder, 15% (683) of mood disorder and 13% (585) had a neurotic, stress-related and psychosomatic disorder diagnosis. People with psychological development disorders like learning or language disorders and autism were the only group of diagnoses with a lower prevalence than the general population (less than 1%).

In terms of which diagnosis came first, of the 2239 people who both accessed mental health services for the first time and had their HIV diagnosis during the study period, 33% of them had contact with mental health services before the HIV diagnosis, and 67% of them had their HIV diagnosis before coming into contact with mental health services.

It is important to acknowledge that SLaM operates in Lambeth and Southwark, the two areas with the highest HIV rates in the country. This means the likelihood of HIV in mental health service users of other geographical areas might be lower than in south London, but potentially still higher than that of the general population in their local area.

Mental health diagnosis often takes time and, on many occasions, people are assessed and seen by the service but might have not yet been diagnosed. However, the study showed that even when removing the 1188 people (27%) who had no identified mental health diagnosis, the likelihood of HIV continued to be higher (2.3%) than that of the general population.

More research might be needed to explore previously recorded mental health diagnoses and patterns of dual diagnosis and co-morbidities, as the study only used people's most recent diagnoses.

This study provides critical data on an overlooked area of research in the UK and presents evidence of the higher rates of HIV amongst mental health service users. However the links between sexual and mental health are complex – the increased prevalence may be because people with mental health needs have a higher risk of acquiring HIV, or that people with HIV have an increased risk of developing mental ill health.

"The researchers highlight the need to better address or support the sexual health needs of people who use mental health services."

There are social factors and inequalities that are associated with an increased risk of both HIV and mental ill health, creating a likelihood of co-occurrence that is hard to pick apart when considering the time delay between illness and diagnosis for both conditions. Furthermore, the prevalence of HIV reported in the study might be an underestimate, as it only accounts for people who have been diagnosed.

The researchers advocate for providing HIV testing in non-HIV specialist services and highlight the need to better address or support the sexual health needs of people who use mental health services, including sexual health testing, treatment, and prevention. They highlight the need for integrated HIV and mental health services and the importance of HIV being known and considered in mental health care plans.

Ideally, integration would mean mental health services can provide routine HIV testing, and links to treatment and care, have a workforce that is aware of sexual health, and include HIV in medication reviews and care planning. Similarly, HIV services would have a workforce that is aware of mental health, provide routine mental health screening, offer low-level support, connect with mental health services, and consider mental health diagnosis and medication in people’s care plans.

Some of these things are meant to happen already according to different guidelines, but it isn’t clear to what extent they do. Increasing and improving the integration between sexual health and mental health services can reduce health disparities in the cohorts of people living with HIV and people with mental ill health.