Opponents of same-sex marriage participate in the March for Marriage in Washington, D.C., on March 26, as the Supreme Court hears arguments on California's Proposition 8 ban on same-sex marriage. Nicholas Kamm/AFP/Getty Images hide caption

itoggle caption Nicholas Kamm/AFP/Getty Images

Amy Goyer moved back to Phoenix to look after her father, Robert, when he began to show signs of Alzheimer's. He is just one of 5 million Americans living with the disease. Sarah Brodzinski hide caption

itoggle caption Sarah Brodzinski

Despite significant advances in neurology and imaging, researchers still don't have simple lab tests for diagnosing patients with mental disorders. Diagnoses are still mostly based on a patient's signs and symptoms. BSIP/UIG via Getty Images hide caption

itoggle caption BSIP/UIG via Getty Images