WEDNESDAY, Jan. 23 (HealthDay News) -- There's a link between depression and anxiety symptoms and temporomandibular joint (TMJ) disorder pain, a condition that affects the jaw, according to a new study.

TMJ disorders affect the muscles and joints that connect your lower jaw to the skull.

This study by German researchers included more than 4,000 patients who underwent medical and oral health examinations and TMJ pain assessments, and completed a psychiatric risk factor questionnaire.

The researchers found that depressive symptoms were more strongly related to TMJ pain than to muscle pain, while anxiety symptoms were linked with muscle pain. The findings were published in a recent online issue of The Journal of Pain.

TMJ pain may be a physical symptom of depression or anxiety, according to the researchers. They explained that these mental health conditions could lead to increased activity in the jaw muscles that could cause inflammation and pain.

It's also possible that chemical imbalances in the brains of people with depression and anxiety could lead to abnormal processing of pain sensation, according to Dr. Stefan Kindler of the department of oral and maxillofacial surgery/plastic surgery at the University of Greifswald and colleagues.

Previous research has suggested a link between depression and TMJ pain, the authors of the new study pointed out in a news release from the American Pain Society. Based on their findings, Kindler's team concluded that there is a moderate to strong link between depression and anxiety symptoms and TMJ pain.

However, the association between TMJ pain and anxiety and depression does not prove that there is a cause-and-effect relationship.

More information

The American Association of Oral and Maxillofacial Surgeons has more about temporomandibular joint disorders.