Study Finds Increased HIV Incidence Among People Using Mental Health Services

People who use mental health services in South London have a significantly higher prevalence of HIV compared with the general population in the same area, with rates about 2.5 times higher, according to a recent study published in BMJ Open.

This finding is based on data encompassing 181,177 individuals who had their first contact with mental health services at South London and Maudsley (SLaM) National Health Service Trust between 2007 and 2018.

Among this group, 4481 (2.47%) individuals had a recorded HIV diagnosis at any point in time—before, during, or after contact with mental health services—equating to a HIV prevalence of 24.73 cases per 1000 people.

In comparison, with approximately 1.3 million residents living in Lambeth, Southwark, Lewisham and Croydon—boroughs in South London—the prevalence of HIV in this area’s general population was approximately 10 cases per 1000 people in 2019.

Among those with HIV in the sample, 18% had a diagnosed substance use disorder, 15% had mood disorders, 13% had neurotic and stress-related disorders, and 12% had unspecified mental health diagnoses. Individuals with a diagnosed substance use disorder had the highest HIV prevalence at 3.77%.

It's worth noting that around 27% of the study sample did not have a formal mental health diagnosis. However, even after they were excluded in an analysis, the HIV prevalence remained high at 2.31%.

“Reasons for this include: (1) diagnosis takes time—it may be too early in the illness for a formal diagnosis to be made and recorded; (2) people may have been referred to mental health services and assessed, and therefore be in the mental health notes system, but not have had a diagnosable mental illness and not taken on by services,” the authors noted.

Additionally, most people (67%) in the study who had HIV received the diagnosis before having contact with mental health services.

The authors emphasized that the relationship between HIV and mental illness is complex.

“The increased prevalence of HIV among people in contact with mental health services could be a real increase resulting from people with mental health needs being more at risk of acquiring HIV, or from people with HIV being more likely to develop a mental illness,” they said. “However, there is the possibility that people with mental illness are more likely to be tested for, and identified as having HIV, compared with the general population due to being in contact with mental health services. Although this seems unlikely as other studies have found that mental health and drug-related hospital admissions were common among people living with undiagnosed HIV.”

There are also environmental factors like social inequalities, which are associated with both increased risk of HIV and increased risk of mental illness, making it even more likely the 2 conditions will both occur in the same person.

The findings of this study underscore the need for further investigation into risk factors and disparities in HIV outcomes between those who are and are not utilizing mental health services.

“The real picture is likely to be a combination of all these things,” the authors said.

Reference

Heslin M, Jewell A, Croxford S, et al. Prevalence of HIV in mental health service users: a retrospective cohort study. BMJ Open. 2023;13:e067337. doi:10.1136/bmjopen-2022-067337