Depression and how it relates to sleep apnea comes up a lot in discussions.  
The following are links to discussions and articles on the subject:


Click here to different forum discussions on topic

Here's one article on the subject:
Click here for link to article

Here's another article about a Stanford study on the subject:
Click here for 2003 article on Stanford study

Here's another Stanford article, more recent, in the Annals of General Psychiatry on the same subject:
Click here for different Stanford study

Another Interesting Link related topic:
Click here for another Interesting Links topic on this subject, with article