We bang on from time to time about high blood pressure increasing your risk of stroke and heart attack. But can it make you a little nutty?

A new and complex study found that high diastolic blood pressure – the lower of the two numbers in a blood pressure reading – can cause neuroticism.

Or putting it another way, it can lead to an increase in neurotic behaviour such as perfectionism, self-criticism, irritability and dissatisfaction – all underwritten by a measure of obsession.

What is neuroticism?

Neuroticism is a personality trait, and not a mental health condition.

While neurotic behaviours are, in the main, of a negative persuasion, they can be useful – with the obsessive aspect presenting as persistence and a pursuit of perfection.

There are self-protective benefits to be gained from maintaining a sceptical view of others.

We all have neuroticism, known as one of the big five personality traits, in our make-up.

The other four traits are agreeability, extraversion, conscientiousness, and openness.

Neuroticism as a gateway to trouble

In healthy people, the other traits keep neuroticism in check so that it doesn’t interfere with functioning, although it can be, even in milder presentations, hard on relationships.

However, people with elevated levels of neuroticism “respond poorly to environmental stress, interpret ordinary situations as threatening, and can experience minor frustrations as hopelessly overwhelming”.

Neuroticism is not the same as neurosis, which is “a diagnosable psychological disorder that interferes with quality of life without disrupting an individual’s perception of reality”.

However, neuroticism can feed into serious mental health issues, and is being recognised as a public health issue because it provides “a dispositional vulnerability for a wide array of different forms of psychopathology, including anxiety, mood, substance, somatic symptom, and eating disorder”.

What’s the link with high blood pressure?

The relationship between mental health and high blood pressure isn’t fully understood, but it appears to be a two-way dynamic.

As a 2014 study observed: “Patients with chronic conditions like hypertension may experience many negative emotions which increase their risk for the development of mental health disorders, particularly anxiety and depression.”

And as an explainer from the Mayo Clinic advises: “Anxiety doesn’t cause long-term high blood pressure (hypertension). But episodes of anxiety can cause dramatic, temporary spikes in blood pressure.

“If those temporary spikes occur frequently, such as every day, they can cause damage to blood vessels, the heart and kidneys, as can chronic high blood pressure.”

And here is where it gets even nastier: People who are anxious or stressed “are more likely to engage in unhealthy habits that can raise blood pressure, such as smoking, drinking alcohol and over-eating”.

All of these can gallop you to stroke country.

For more on the relationship between hypertension and mental health, see here.

The new study

Shanghai investigators, using a sophisticated tool called Mendelian randomisation, sought genetic evidence for a causal relationship between four components of blood pressure (systolic blood pressure, diastolic blood pressure, pulse pressure, and hypertension) and four psychological states (anxiety, depression, neuroticism, and subjective wellbeing).

The study involved eight large-scale study datasets containing whole genome DNA extracted from blood samples from people of predominantly European ancestry (genome-wide association studies).

The significant finding was a relationship where diastolic blood pressure (measured in between heartbeats) has a “genetic causal effect on neuroticism”.

The researchers concluded appropriate management of blood pressure “may reduce neuroticism, neuroticism-inducing mood disorders, and cardiovascular diseases”.

In other words, fix hypertension, and you might go some way to fixing the mind and the heart.