Non-physical factors can also lead to disturbed sleep. Depression is commonly
associated with or complicated by insomnia. One of the most common signs of a major
depressive episode is sleep disturbance characterized by early morning awakening.
(Ref. 13) Worry, tension, or anxiety can cause insomnia by interfering with the ability to
relax and fall asleep. Patients with chronic insomnia often develop poor sleep habits,
and attention to improving these habits (i.e., practicing good sleep hygiene) can lead to
improved sleep. (Ref. 1) Patients who are hospitalized or must sleep away from home
for cancer treatments may suffer from sleep disturbance as a consequence of being in
an unfamiliar environment at night, with unfamiliar surroundings or intrusive ambient
noises.