Mental health and heart disease

Two new studies have shown that mental health and heart disease are closely linked.

One study showed that people who’ve experienced depression are more likely to go on to have a heart attack. In the other study, the relationship of cause and effect was the other way round – people with high cholesterol were more likely to go on to lose some memory and mental processing skills.

So, taking steps to protect your mental health and get treatment if necessary is likely to also have benefits for the health of your heart. And taking care of your cholesterol may also help keep you mentally alert in the coming years.

The relationship between these issues has already been demonstrated in the general population. But these are the first studies to show that this applies to people living with HIV as well.

Depression and heart attack

The first study enrolled over 26,000 people living with HIV in the United States. Almost all were men and their average age was 47. When they joined the study, rates of depression were high – 19% had a ‘major depressive disorder’ and 9% a milder form of depression.

A major depressive disorder is defined by psychiatrists as a period of at least two weeks of persistently low mood accompanied by symptoms such as feelings of worthlessness, anxiety, pessimism, impaired concentration, disturbed sleep, loss of interest in everyday activities, reduced energy, and sometimes, thoughts of death or suicidal feelings.

Following up each person for an average of six years, 2% of the people in the study went on to have a heart attack. They found that people who had had ‘major’ depression were 30% more likely to have a heart attack.

But people who had had major depression and took antidepressant medication for it did not have a higher rate of heart attacks. Studies in HIV-negative people have also shown that by treating depression, you can reduce your risk of heart problems.

In this study, people living with HIV who had the milder form of depression were not more likely to have heart attacks.

People who have depression have physical changes in their body. These changes are thought to be the reason for the increased risk of heart disease.

The changes include over-activation of the immune system, over-activation of the parts of the nervous system that control involuntary actions like the beating of the heart and the regulation of blood pressure, and hormonal changes that affect their response to stressful events.

It’s also possible that people with depression have less healthy lifestyles – for example smoking more or exercising less – and this could explain some of the relationship.

Cholesterol and cognitive decline

The other study looked at a different aspect of mental health – people’s memory, attention span, mental processing skills and motor skills. When this got worse over time, the researchers describe it as ‘cognitive decline’.

In this study, the relationship of cause and effect was the other way round – people who had high levels of cholesterol at the beginning of the study were more likely to go on to have cognitive decline.

This was a smaller study, but also focused on men living with HIV in the United States. They were all aged between 50 and 65, and were all doing well on HIV treatment.

Compared to a comparison group of men without HIV, there was a faster rate of cognitive decline. Over six years of follow-up, there was more cognitive decline in men who had high levels of ‘bad’ LDL cholesterol and high levels of triglycerides at the beginning of the study.

Cholesterol and triglycerides are lipids, in other words fats in the blood. They are an important measure of heart health.

Importantly, men with HIV who took statin treatment to lower their levels of ‘bad’ cholesterol had less cognitive decline.

Again the study highlights the close links between the heart and the brain. If the heart is unable to effectively pump blood, oxygen and nutrients to the brain, brain cells can die.

Taking part in ‘cure’ studies

According a recent Australian survey, 82% of people living with HIV would be willing to take part in a study towards a cure for HIV. But they would be less willing to participate if it:

  • would increase their susceptibility to illness (87%)
  • risked developing resistance to current antiretrovirals (79%)
  • resulted in an unpredictable viral load for up to a year (63%)
  • involved weekly visits to a medical clinic for several months (40%).

Researchers emphasise that people are right to be cautious. Studies which are currently working towards possible cures for HIV are still at an extremely early stage. It’s highly unlikely that individuals who take part in these studies will see any improvements in their own health as a result of being in a study. But taking part in a clinical study always involves some risk – the potential for harm cannot be excluded.

An American survey showed that people with HIV often have several reasons for being interested in taking part in a cure study. Altruistic reasons were very important – helping find a cure for HIV and helping others with HIV in the future were mentioned by very many. People also hoped to find out about their health and get better access to medical care.

But many people also hoped that taking part in a study might have clinical benefits. For example, they hoped it could increase their immune system’s ability to fight HIV, reduce the reservoir of HIV in their body or control viral load without treatment.

Researchers warn that, at this stage, such personal benefits are unlikely. They say that knowing you are contributing to advancing medical knowledge is a more realistic expectation to have. Taking part is more likely to have benefits for the wider society than for the individual concerned.

They say that it’s vital that cure scientists engage with and educate people with HIV on what they are doing. When asking people with HIV to take part in studies, they need to be transparent about what the study will involve and what its outcomes are likely to be.

They have an ethical duty to talk clearly about the risks of taking part. Some risk is inevitable, but it must be reasonable in relation to the scientific importance of the research knowledge that might be produced.

You can find out more about taking part in studies in NAM's factsheets 'Clinical trials' and 'Thinking about joining a clinical trial?'