As defined by DSM-IV-TR, the diagnosis of major depression
can be made on the basis of the presence of 5 of 9
depressive symptoms. In addition to the current symptomatology,
an adequate assessment also includes personal or family
history of past depressive episodes, history of suicidality, and
history of substance abuse, as all of these can influence prognosis
for the current episode of depression (Table 2). Also
important are past treatment trials and response (to guide
current treatment), and assessment of current suicidal ideation
and imminent risk of self-harm (to guide location of
treatment, inpatient versus outpatient). Cognitive status
should be assessed with the Mini-Mental State Examination
(MMSE), given the high likelihood of comorbid depression
and cognitive dysfunction.28 Because a variety of medical
conditions can mimic depression in old age, a minimum
workup includes basic metabolic panel, complete blood count,
thyroid function tests, and serum vitamin B12 and folate
levels. Nutritional status is important to evaluate in the depressed
elder, especially the oldest old, given the risk for frailty
and failure to thrive in depressed elders.29,30 Laboratory tests
need not be repeated if they have been performed in the past
year, or since onset of depressive symptoms, whichever is
more recent. A review of current medications is also essential
because of the long list of medications that can cause symptoms
similar to those of depressive disorder. Unless a medication
is thought to definitively contribute to significant
depressive symptoms and safer alternatives are available,
discontinuation of medications for other indications may not
be a viable option in this population, which often has significant
medical comorbidity