A common treatment for obstructive sleep apnea can significantly reduce symptoms of depression in those with cardiovascular disease, a new study says.

Australian investigators followed more than 2,600 patients for an average of 3.7 years and found that those who had continuous positive airway pressure treatment experienced a significant – and lasting – reduction in depression symptoms compared with those not treated for obstructive sleep apnea. Patients with lower mood scores at the study’s start had the most benefit from a CPAP regimen, they wrote.

Stroke, sleep apnea and depression are closely linked. Up to 50% of stroke and heart attack patients are likely to suffer from obstructive sleep apnea, and are also two-to-three times more likely to develop clinical depression, explained principal investigator Doug McEvoy, M.D. Depression, in turn, compounds the risk of future heart attack and stroke, he added.

The study’s results are “welcome news that treatment of OSA substantially relieves cardiovascular patients’ depressive symptoms and improves their wellbeing,” McEvoy concluded.

The researchers used data from the Sleep Apnea Cardiovascular Endpoints trial led by Flinders University. The study was published in the May-June issue of the Lancet in EClinicalMedicine.