The first study to show a relationship between depression and sleep apnea found that individuals with depression are 5 times more likely to have a breathing-related sleep disorder, compared with non-depressed people. The association between the 2 conditions remained strong even after controlling for obesity and hypertension. These findings were published in the Journal of Clinical Psychiatry (November 2003).
To investigate the impact of depression and sleep apnea in the general population, the researchers conducted a telephone survey of >18,000 adults in 5 European countries. The participants answered questions on sleep quality and schedules, breathing-related sleep disorders, mental disorders, and medical conditions. The results showed that 2.1% of the respondents had sleep apnea and 2.5% had another type of breathing-related sleep disorder. Participants who were experiencing a depressive disorder (18%, or 4% of all the participants) also had a breathing-related sleep disorder, compared with 3.8% of non-depressed participants.