association between depression and severity of obstructive sleep apnea syndrome

background and objective: depression is commonly reported in patients with obstructive sleep ap- nea/hypopnea syndrome (osas). we aimed to assess the association between osas severity and depressive symptoms in patients with osas. materials and methods : a total of 337 patients with symptoms of osas were visited for psychological testing prior to beginning diagnosis for the syndrome between 2012 -2014 in baharloo hospital. participants completed the beck depression inventory-ii (bdi-ii) and epworth sleepiness scale (ess) questionnaires. res- piratory disturbance index (rdi), mean of arterial oxygen saturation, sleep efficiency, and number of awaken- ings were measured by polysomnography (psg). results : correlation between rdi index and ess score was statistically significant (r: 0.215, p <0.001), but correlation between rdi and bdi-ii score was not statistically significant ( p = 0.59). also mean of bdi-ii score between male and female was statistically different (male: 12.08 ± 10.6, female: 17.26 ± 12.56, p <0.001). conclusions : osas severity was not related to symptoms of depression measured by bdi-ii questionnaire.it seems that the method of scoring for depression severity may affect the association between obstructive sleep apnea and depression.