Effect of CPAP treatment on mood states in patients with sleep apnea

Sleep apnea can lead to marked psychological distress including some mood s ymptoms. Previous studies on continuous positive airway pressure (CPAP) tre atment usually reported significant improvement in mood symptoms in patient s with sleep apnea, but most of them did not consider the placebo effect of CPAP. We examined the effect of CPAP treatment on mood states by employing both CPAP treatment and placebo CPAP. Twenty five men and nine women with sleep apnea underwent two successive nights of polysomnography (PSG) during hospitalization. The Profile of Mood States (POMS) was administered to mea sure mood states. Patients were randomly assigned to either CPAP treatment group or placebo CPAP group. After 7 days of CPAP use at home, all patients were re-hospitalized to undergo one more night of nocturnal PSG with their assigned treatment (CPAP treatment or placebo CPAP). They also had a repea t evaluation of mood by completing the POMS. Only patients on CPAP treatmen t improved significantly in apnea index, respiratory disturbance index, and mean oxygen saturation. However, both CPAP treatment group and placebo CPA P group showed significant improvement in mood states. In conclusion, the e ffect of CPAP treatment on mood symptoms in apneic patients could be a plac ebo effect. CPAP treatment may be effective in improving mood states only i n patients who have severe depressive symptoms secondary to sleep apnea. (C ) 1999 Elsevier Science Ltd. Ail rights reserved.