Patients who experience symptoms, such as sleepiness, fatigue, poor motivation, irritability, and difficulty concentrating, are often diagnosed with depression and are treated with antidepressants.

A new study suggests that many of these patients have obstructive sleep apnea (OSA), and their symptoms may be reduced with continuous positive airway pressure (CPAP) therapy.

Researchers from The Sleep Center at University Community Hospital, Tampa, FL, found that 38 percent of patients were receiving antidepressant medication, and, after using CPAP therapy consistently for 4 to 6 weeks, 98 percent of patients showed improvements in depression and sleep scores.

Researchers speculate that these patients were misdiagnosed with depression and actually had OSA or patients had related OSA events and subsequent sleep fragmentation that possibly affected the brain and caused depression.

It is also possible that OSA and depression share an underlying mechanism. Researchers suggest that physicians test patients presenting with symptoms of depression for OSA and, if necessary, offer CPAP treatment. The study appears in the September issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians.