* Persistent feelings of sadness, apathy, or hopelessness lasting more than two weeks.

* Diminished interest in most daily activities, particularly pleasurable ones.

* Decreased appetite and subsequent weight loss; increased appetite and weight gain.

* Lack of sleep (insomnia), frequent awakening throughout the night, or conversely, an increased need for sleep.

* Anxiety; diminished ability to think or concentrate.

* Older people may initially focus on physical or cognitive complaints brought on by their depression. Insomnia and agitation are also more common in older patients.