Based on their findings, the investigators suggest that medical treatment with CPAP, for example, or behavioral modification of sleep-related breathing disorder, with weight loss, for example, "may help mitigate or prevent depressive symptoms" in these patients.

The findings are from the Wisconsin Sleep Cohort Study, which began recruitment in 1988 of subjects between 30 and 60 years old. The subjects were scheduled to undergo overnight sleep studies in a laboratory every 4 years. The study cohort was comprised of 1408 participants with 3202 sleep studies.

Dr. Paul E. Peppard and colleagues at the University of Wisconsin-Madison observed significant dose-response trends of increasing risk of depression with increasing sleep-related breathing disorder severity.

After adjusting for age and gender, the odds ratio of depression when compared with no breathing disorder was 1.6 for minimal sleep-related breathing disorder, 2.0 for mild sleep-related breathing disorder, and 2.5 for moderate or worse sleep-related breathing disorder.

Fully adjusted longitudinal data showed that a two-category transition -- for example, from no sleep-related breathing disorder to mild sleep-related breathing disorder -- was associated with an odds ratio for depression of 3.3.

SOURCE: Archives of Internal Medicine September 18, 2006.