Not sure. Major depression disrupts many body functions, including sleep and appetite--but it can affect both in either direction. Some people sleep much more, others much less; some have no appetite and lose lots of weight, others overeat and gain weight. Exactly why presentation can vary so much among people remains an area of intense interest.
Depression. Sleeping and isolation can be and "escape", for those depressed. These can forgo more serious problems and help should be seeked.
Not always true . . Depression can alter sleep patterns, as can stress, diet, anxiety, alcohol, work, medications & lack of exercise. Depression can result in changes in neurotransmitters such as serotonin, Dopamine & norepinephrine, which influence sleep. Some types of depression are associated with agitation, which may decrease sleep, and some depressions are characterized by fatigue, which may increase sleep. Read more...