The criteria of the Diagnostic and Statistical Manual of Mental Disorders (4 th ed.; DSM-rV) for depression require that symptoms are not direct physiologic effects of a general medical condition or medications used to treat it. However, in older patients, this distinction may be difficult to make, as depressive symptoms can overlap with those of concurrent medical illnesses and side effects of medications (Cobbs, Duthie, &
Murphy, 2002). Many medical disorders that are more prevalent in the elderly may mimic depression and deserve consideration, like hypo or hyperthyroidism, Parkinson's disease, or dementia.