Teething problems

Deakin researchers are on the brink of a breakthrough field of research that is making connections between dental health, diet and mental health.

Using data from a comprehensive health survey of more than 10,000 people aged 20-75 living in the United States, researchers from Deakin's IMPACT Strategic Research Centre have found that poor dental health (as measured by the number of dental conditions a person has) increases the likelihood of being depressed.

This finding has implications for the causes and treatment of depression.

“Not only did we find a connection between dental health and depression, but we also demonstrated that a dose-response exists between the two conditions, meaning that the more dental conditions one has, the greater the severity of their depression,” said Deakin’s Dr Adrienne O’Neil, who is currently completing the second year of her Alfred Deakin Postdoctoral Research Fellowship.

The researchers found that almost two thirds of participants reporting depression (61 per cent) also reported having an aching mouth in the past year and more than half (57.4 per cent) considered their teeth to be in fair or poor condition.

But the discomfort of having to put up with toothache – painful as it is - is unlikely to be the cause of the depression.

Researchers now consider depression an inflammatory disorder, meaning that sources of inflammation such as bad dietary habits, being overweight, or having certain other medical conditions, can contribute to the biological processes that induce mental disorders from a very early age.

However, the research in this field is only just beginning. Poor dental health, which is a source of inflammation, has not been investigated extensively in the context of its links with mental health.

“The relationship between dental health and depression is not well understood, with previous studies investigating poor dental health as a by-product of depression, rather than a precursor,” Dr O’Neil said.

“The results of this study add to emerging theories around the importance of oral health and bacteria in mental health.

“This is an exciting area of research that Deakin is exploring further, through a longitudinal study in Australia of how microbiota and bacteria in the mouth, as well as the gut, may be related to inflammatory disease, including depression.

“If poor dental health is a risk factor for depression, this may have implications for depression management, as well as depression prevention from a public health perspective.”

More information about this project can be found at:

• General Hospital Psychiatry