People living with HIV in the UK have an increased risk of mental illness

A study by Tiffany Gooden and colleagues in the Lancet HIV shows how people living with HIV in the UK are at higher risk of developing mental illness than people without HIV. During the study, people living with HIV had a 63% greater risk of being diagnosed with mental illness, compared to people without HIV.

It has been well documented that the prevalence of mental illness (including depression, anxiety, and severe mental illness) is higher amongst people living with HIV. However, this is probably the first study to report new cases of these conditions in people living with HIV, using a matched cohort population-based approach, therefore providing better evidence of the disproportionate impact of mental illness in people living with compared to people without HIV.

The study was conducted between 2000 and 2020 using data from a large UK primary care database to compare new mental illness in 7167 people living with HIV and a control group of people without HIV, who had no diagnosis of mental illness.

The matching process of both groups was based on region, age, sex, ethnicity, deprivation, smoking status, body-mass index, substance use, cardiovascular disease, hypertension and diabetes. The researchers also look at these variables to draw conclusions on how the increased risk of mental illness varies in different groups of people living with HIV.

Their findings show that 586 people living with HIV developed mental illness, compared to 418 people without HIV in 20 years of the study (incidence rate of 19.6 and 12.1 per 1000 people-years, respectively). This means that for every 1000 people with HIV followed for a year, 19 people would be expected to develop mental illness.

More specifically, they found a higher incidence of depression, anxiety, and severe mental illness (such as psychosis, schizophrenia, and bipolar disorder) in people living with HIV than in people without HIV. 495 people living with HIV developed depression, 266 anxiety and 64 severe mental illness, compared to 298, 214 and 30 respectively in people without HIV.

Risk changed most notably with sex, showing men living with HIV had two times increased risk of mental illness compared to those without, whilst women didn’t present any differences between the two cohorts.

The risk of mental illness was elevated for those living with HIV irrespective of age, deprivation and smoking status, and the risk did not decline over the 20-year of study. 

People living with HIV who were White, not obese or who did not use drugs or drink heavily, had an increased risk of mental illness whereas those from ethnic minorities, obese or who misused substances did not.

Severe mental illness (such as psychosis, schizophrenia, and bipolar disorder) was reported as higher amongst those living with HIV in the most deprived groups and those diagnosed in the early stages of the study (2000-09).

However, this study has some limitations. It was conducted at a time (2003-2015) when efavirenz was commonly prescribed, and its side effects (including mood disturbances) might have been recorded as mental health conditions. 

Additionally, their data set didn’t include the mode of transmission and sexual orientation, and the prevalence of HIV found (0.11%) is lower than national estimates (0.15%) potentially due to people not sharing their status with their general practitioner.

These limitations mean further studies are needed to investigate the increased risk of mental illness in people living with HIV. They also heighten the importance of understanding the biological mechanisms and psychosocial factors (including stigma) that act as drivers and barriers to screening and diagnosing mental illness.The higher rates of mental illness diagnoses amongst people living with HIV in the study can be due to higher contact with healthcare professionals, persistent immune activation caused by HIV infection, stigma and discrimination, and existing socio-economic inequalities. 

HIV and mental health are syndemic, and poor mental health can be both a risk factor and a potential consequence of HIV. It is amongst the most common comorbidities experienced by people living with HIV. This personal and public health crisis impacts well-being and quality of life, exacerbates existing inequalities and can lead to treatment disruption, which can result in further transmission of HIV.

The findings of this study are relevant not only in the UK but in other high-income countries too. People living with HIV are more likely to be diagnosed with depression, anxiety and severe mental illness than those without HIV.

Therefore, people living with HIV should continue to be regularly screened for symptoms of mental illness, reached by effective interventions that prevent and manage mental illness, and targeted by outreach programmes that ensure key communities are not being underdiagnosed.