Discerning depressive symptoms in patients with obstructive sleep apnea: the effect of continuous positive airway pressure therapy on Hamilton Depression Rating Scale symptoms.

The assessment of depression in obstructive sleep apnea (OSA) is confounded by the overlap in symptoms between the disorders. However, previous analysis by our group has suggested that while some depressive symptoms tend to overlap with OSA (such as insomnia, lethargy, impaired concentration, psychomotor retardation) other, nonoverlapping symptoms appear more specific to depression (such as negative affect, anhedonia, and depressive cognitions). We sought to determine the value of such categorization of depressive symptoms in identifying clinical depression within OSA patient populations by examining the response of these two categories of depression symptoms to treatment of OSA by continuous positive airway pressure (CPAP).