In his book Underneath the Lemon Tree, Mark Rice-Oxley describes vividly how his clinical depression robbed him of the ability to sleep. He would spend the night pacing the room downstairs while simultaneously locked into a cycle of terrible rumination. Many depression sufferers resort to sleeping tablets and MRO was on the wonderfully named Zopiclone. I, too, took Zopliclone to help me sleep in the early days of my illness. I, too, had to sleep in another room to prevent disturbing my partner.
However, depression can also have the opposite effect on your sleep pattern - i.e. making you sleep for much longer than normal. It can also make it dreadfully hard for you to get up in the morning. In some ways, this seems to be a more understandable feature of depression as many of us associate the illness with lethargy and demotivation. After my initial problems with sleep, I flipped over into 'sleeping for England' mode. I could (still can) sleep solidly for 10 hours at a stretch. Sleep also has the added advantage of providing an escape from negative thoughts and can be a welcome refuge. Even today I look forward to bedtime and the oblivion it provides. Waking up on the other hand can be a distressing experience - once you slowly regain consciousness and realise that you are still the same person stuck in the same world.
As I also suffer from chronic dizzinesss - sleep provides a double relief and I do find that after a good night's sleep I do feel slightly better the next morning.
'Sleep that puts each day to rest. Sleep that relieves the weary laborer and heals hurt minds. Sleep, the main course in life's feast, and the most nourishing.'
Macbeth -William Shakespeare