Prevalence of depression in patients referred with snoring and obstructive sleep apnoea

BACKGROUND AND AIMS: Depression and obstructive sleep apnoea are two common entities, with common symptoms that make identification of either condition difficult. Our aim was to examine, within a group of patients referred with snoring and obstructive sleep apnoea, (i) the prevalence of depression with the 14-question Hospital Anxiety and Depression Scale (HADS), (ii) the correlation between the two lead depression symptoms from the Mini-International Neuropsychiatric Interview (MINI) and HADS, and (iii) the relationship between depression symptoms with physiological markers of OSA. METHODS: An observational study of depression questionnaires in patients referred because of snoring to a sleep clinic within university-affiliated public teaching hospital. RESULTS: Ninety-seven per cent of 240 patients approached responded, and 32% had a positive HADS (score >16/42). The HADS and MINI significantly correlated (r = 0.736, P < 0.001). Fifty-three per cent had either doctor-diagnosed depression (28%) and/or a positive HADS or MINI (25%). HADS correlated with the degree of sleepiness (r = 0.252, P < 0.0001) and inversely with hypoxaemia (r=-0.231, P < 0.0003) but not with the frequency of apnoeas and hypopnoeas (r = 0.116, P > 0.05). CONCLUSION: Depending on classification, 32-53% of patients with snoring had depressive symptoms or were on treatment, which is significantly greater than the Australian average of 21%. A simplified depression questionnaire was validated. Severity of depression correlated with sleepiness and hypoxaemia but not with severity of sleep apnoea.