The SAD Study - SLEEP, ANXIETY & DEPRESSION Study A Prospective Cohort Study

The prevalence of anxiety and depression in our OSA population is more than in COPD and the general population of North West Adelaide. (principal hypothesis).

CPAP therapy in OSA population produces a positive effect on the anxiety and depression scale.

The Investigators intend to study the prevalence of anxiety and depression in patients with sleep disorders in comparison to patients with COPD and subsequently, to assess whether CPAP has a role in controlling anxiety and depression in depressed and anxious patients with sleep apnoea.

This is a two phase study, in first phase; investigator will assess the prevalence of anxiety and depression, in a population with sleep disorders to check whether it is different to the prevalence in the COPD population. The prevalence of depression in Sleep Disorder population will also be compared with the Adelaide North Western general population, which was reported in The North West Adelaide Health Study. According to this epidemiological survey, which was conducted from 2008 to 2010, the prevalence of depression in Adelaide North Western general population was 20%.During the second phase of the study investigator will evaluate the effect of CPAP on anxiety and depression scores in the depressed and anxious patients with sleep apnoea by comparing the pre and post CPAP anxiety and depression status. The Hospital Anxiety and Depression (HAD) scale will be used to assess Anxiety and Depression, which is a well-documented tool for assessing symptoms of anxiety and depression in patients with somatic diseases.