Posting some links to articles about sleep architecture, depression, and medications. These factors can affect your sleep study results and also increase or decrease apneas.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181772/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119746/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181883/
http://www.nature.com/npp/journal/v28/n ... 0029a.html