Depression and anxiety, both as symptoms and as formal disorders, are elevated in patients with chronic medical disorders, including obstructive sleep apnea, for which continuous positive airway pressure (CPAP) treatment is the standard of care. To study the relationship of CPAP to depressive and anxiety symptoms, investigators performed an analysis of data from an international, randomized, controlled, prospective study examining the effectiveness of CPAP treatment for secondary prevention of cardiovascular disease in 2410 participants. The participants mean age was  61; mean body-mass index of about 28.6 kg/m2;and mostly men,( 81%).


In addition to coronary artery disease (55%) and cerebrovascular disease (50%), comorbidities included hypertension (79%), diabetes (30%), and frequent alcohol use (26%). At baseline, patients’ self-rated depression symptoms suggested possible or likely depressive disorder in 26% of individuals and for anxiety disorders in 20%. At follow-up (mean, 3.7 years) in analyses adjusting for final daytime sleepiness scores, CPAP patients were significantly less likely than usual-care controls to have depression  (18% vs. 25%. No group differences were seen in anxiety.


The authors also performed a meta-analysis of 17 CPAP studies with depression ratings, 13 of which reported anxiety ratings. The meta-analysis confirmed CPAP’s superiority to control approaches for reducing depressive symptoms (modest effect size) but not anxiety. So, although anxiety does not appear to improve with CPAP treatment, it is quite possible that symptoms of depression do improve.