Bruxism is the involuntary excessive grinding, clenching or rubbing of teeth and can occur during the day or night. Scientists think that between 5-8% of adults grind their teeth but the links between bruxism and psychological factors are not conclusive and their relationship is still not fully explained. Turkish researchers compared levels of depression and anxiety in 58 people with, and 41 people without, bruxism. They found that levels of depression and anxiety were significantly higher in people who ground their teeth.
Gungormus, Z. and Erciyas, K. - Evaluation of the relationship between anxiety and depression and bruxism Journal of International Medical Research 37(2), 547-550