NEW YORK (Reuters Health) - People who have a severe problem with nighttime teeth grinding appear to be more likely to use alcohol, cigarettes, and caffeine daily, according to the largest study to date of this habit.

What's more, people with the problem--known as bruxism--may be more likely to have anxiety, depression or certain types of other mental illness.

About 8% of the 13,057 participants in the study reported grinding their teeth during sleep at least once a week, researchers from the Stanford University School of Medicine's Sleep Disorders Center found. The findings are published in the January issue of the journal Chest.

More than half of the tooth-grinding individuals--4.4% of all study participants--said they had discomfort in their jaws when they woke up, disturbed their bed partner with their tooth grinding, or needed dental work because of their tooth grinding. This means that they met the official criteria for having sleep bruxism. Sleep bruxism is the third most common sleep disorder, after talking in one's sleep and snoring.

"Sleep bruxers" were also more likely to feel they were choking and couldn't breathe during sleep, to wake up during the night, and to have morning headaches, the researchers found. Sleep-bruxers and tooth-grinders were also more likely to talk in their sleep and to exhibit "violent or injurious behaviors" during sleep.

Those with sleep bruxism were more likely than non-teeth grinders to drink alcohol at bedtime (5% vs. 3%), drink at least one glass of alcohol during the day (8% vs. 5%), drink at least six cups of coffee each day (25% vs. 16%) and smoke daily (35% vs. 23%).

Certain types of mental illness were also more common in the individuals with sleep bruxism, including difficulty adjusting to stressful situations (4% vs. 2%) and bipolar disorders (7% vs 2%). Also, the tooth-grinders and sleep-bruxers were more likely to suffer from anxiety disorders and clinical depression than non-tooth grinders.

About 69% of people in the study with sleep bruxism said their problem was related to stress or anxiety.

According to the researchers, their findings suggest that sleep bruxism could be associated with sleep apnea (difficulty breathing during sleep), a condition with serious medical consequences.