Depression is four times more likely to strike those over age 65 than younger individuals. It is found in 20 percent of persons with Alzheimer's disease, in up to 50 percent of Alzheimer caregivers, and in 15 percent of adults over age 65. Most people never seek help for this treatable illness.

• Depressed or irritable mood
• Feelings of worthlessness, self-reproach, or excessive guilt
• Suicidal thinking or attempts
• Motor retardation or agitation
• Disturbed sleep
• Fatigue and loss of energy
• Loss of interest or pleasure in usual activities
• Difficulty in thinking or concentrating
• Changes in appetite and weight