Over-the-counter painkillers such as aspirin and ibuprofen could offer hope for a breakthrough treatment for depression, researchers say.

While cautioning that the theory is still a work in progress, experts say it appears the anti-inflammatory effect of common painkillers might mitigate depression in some patients.

“Far more research is needed about the type of tissues and molecules associated with inflammation in the brain and depression, and which kind of drugs work best to treat it,” said Professor Jennifer Stow, from Queensland University’s Institute for Molecular Bioscience.

“Anti-inflammatories that are effective in treating bowel disease and arthritis have not been shown to be as effective for other types of inflammatory disease.”

Anti-inflammatories are used to reduce pain, decrease fever, prevent blood clots and decrease inflammation. Medicines such as ibuprofen, aspirin, celecoxib (sold as Celebrex) and diclofenac (sold as Voltaren) are all common anti-inflammatories available in Australian pharmacies.

Researchers have pointed to a meta-analysis of 14 international studies that suggests that celecoxib might be a treatment option for some kinds of inflammatory-related depression.

People with conditions such as rheumatoid arthritis have a higher risk of depression. Photo: Getty

The hope comes from the similarities scientists have noted between depression and the lethargy and low mood felt by those with bad colds.

These mood and energy “blahs” are caused by the body’s activated immune response, which triggers inflammation in response to injury or infection. The similarities led scientists to question whether the response might actually trigger mental health problems in some people if their inflammation became chronic.

“Research had already shown that people with inflammatory conditions such as rheumatoid arthritis were at higher risk of developing depression,” said Michael Berk, professor of psychiatry at Deakin University’s school of medicine.

“Since then, studies have been exploring whether the inflammation itself might be to blame.”

The studies have found that people with depression have higher levels of inflammatory chemicals, such as cytokines.

“There are numerous different types of markers that indicate that inflammation is going on in the body, including chemicals such as C-reactive protein,” Professor Berk said.

One study at the University of Toronto found that people with clinical depression had 30 per cent higher levels of brain inflammation.

At the University of Manchester, another study found people with major depressive disorder had increased levels of inflammation, particularly in a part of the brain involved in mood regulation.

Persistent inflammation has also been shown to weaken the brain’s reward circuits, meaning it reduces a person’s ability to experience pleasure.

However, the link remains controversial, with other studies showing that people with depression might not have elevated inflammation at all.

Professor Berk said his team was running clinical trials to work out the tissues and molecules associated with brain inflammation and depression – and the drugs that might treat it best.

He is also working on the ASPREE clinical trial, which aims to determine whether aspirin can help prevent a range of conditions including dementia, cardiovascular disease, some cancers and depression in the elderly.

“Aspirin has a well-known anti-inflammatory action and with the large number of people enrolled in our trial – which is around 19,000 people – for the first time, researchers hope to determine whether aspirin can help to prevent depression in older people,” Professor Berk said.

For now, he advised caution before reaching for the medicine cabinet.

“These medications such as aspirin should be used under the guidance of a doctor because they can cause side effects, including bleeding of the stomach,” he said.

Does #aspirin prolong disability-free survival? >80 K human years of #ASPREE data being prepared for analysis, primary paper due early 2018. pic.twitter.com/mfk6thuqD8

— ASPREE (@aspree_org) October 8, 2017

How to reduce inflammation

In the meantime, there are other low-impact ways to treat inflammation in the brain.

Stress, smoking, drinking too much alcohol and eating takeaway food can all hasten its development. Recommended lifestyle changes include:

Eat a Mediterranean diet

“Research shows that people who eat a diet rich in fresh fruit and vegetables, whole grains and lean protein have lower levels of depression and anxiety than those eating a diet high in processed foods,” said Natalie Parletta, an adjunct senior research fellow in nutrition and dietetics at the University of South Australia.

The traditional Mediterranean diet, which is high in plant foods, olive oil, fish and a little lean meat, has been shown to lower inflammation.

“It is high in many nutrients that help reduce inflammation, including antioxidant vitamins found in vegetables such as tomatoes and eggplant, and omega 3 fatty acids found in foods such as fish, nuts, seeds and dark leafy greens,” Dr Parletta said.

Move It

Walk, cycle or hit the gym; regular exercise helps to reduce inflammation.

Get enough zzzzzs

Sleep loss has been shown to increase inflammation. Aim for seven to eight hours of sleep a night.