 Over 18 of Americans aged 65 years and older have depression. Recent evidence suggests that there is a link between depression and inflammatory disease. This study investigates the relationship between inflammation in the brain and depression. Comparing biological and psychological differences in depressed and non-depressed people allows researchers to find better ways to treat and prevent depression. All participants will have: neuropsychological tests, an EKG, a spinal tap, a blood draw, and, if depressed, given either an antidepressant coupled with an anti-inflammatory medication or an anti-depressant coupled with a placebo for six weeks. The investigators are trying to correlate brain function with depression levels and biomarkers from the blood and spinal fluid. 