Your teeth and your brain might not seem like they have much in common, but researchers have consistently found a relationship between mental health and oral health.

For example, a systematic review of studies published in 2015 showed that people with severe mental illnesses tended to have more decayed, filled and missing teeth. Overall, they were 2.8 times more likely to have lost all their teeth.

Several possible explanations have been put forward to the link between mental and oral health. People with mental health problems may have less access to dental treatment and they may have lifestyle differences that affect their dental health.

One possibly underexplored reason, though, is that people with mental illnesses also tend to have a greater fear of dental treatment. A 2013 study of 212 people with mental health disorders found that about 30 percent of them had severe fear of dental treatment.

This was especially true of those with anxiety disorders, who had a sevenfold higher risk for severe fear of dental treatment, and those with depression, who had an almost fivefold higher risk. The people in the PTSD group were at the highest risk of all, being almost ten times as likely as people without mental health disorders to have severe dental treatment fear.

The study also found that more than half of the people with severe fear of dental treatment had missed or canceled a dentist appointment because of their fear.

To make matters worse, it turns out that when people with mental health disorders do seek dental treatment, they can face stigma as a result of their conditions. A study published this month found that people with mental illness perceived being stigmatized when they were shut out of the decision-making process or treated as “different” or “unworthy.” On the other hand, they reported feeling empowered when they received strong communication and empathy from their dental care providers.

While there are likely a range of reasons people with mental health problems also tend to have oral health problems, these findings point to a couple things that can be done to help people with mental health conditions access dental health services. Addressing these people’s fears of dental treatment and spreading mental health awareness among dentists could both make a difference in improving oral health among people with mental illnesses.

Image: Flickr/Ludosphère