High school athlete Graham Hill, number 50, suffered a concussion in 2013 while playing football at Trinity Christian Academy in Addison, Texas. Courtesy of Jeffrey McWhorter hide caption

itoggle caption Courtesy of Jeffrey McWhorter

When he was 59 years old, Greg O'Brien was diagnosed with early-onset Alzheimer's disease. Five years later, he is speaking publicly about his experience, even as his symptoms worsen. Courtesy of Greg O'Brien hide caption

itoggle caption Courtesy of Greg O'Brien

The UASK app helps sexually assaulted college students in D.C. access a range of services, from rides to the hospital to phone numbers for counselors. The information is personalized to their school. Another version of the app, ASK, provides the same resources to non-students. Emily Jan/NPR hide caption

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Mental health therapist Shaundra Drysdale updates daily use numbers inside a crisis support services center in Greeley, Colo. Grace Hood/KUNC hide caption

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A Kaiser mental health worker with the National Union of Healthcare Workers looks through a pile of signs Monday during day one of a week-long demonstration outside of a Kaiser Permanente hospital in San Francisco. Justin Sullivan/Getty Images hide caption

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Sgt. Mark Miranda, a public affairs specialist at Joint Base Lewis-McChord in Washington state, demonstrates the use of a program in July 2011 that was designed to help calm symptoms of post-traumatic stress and traumatic brain injury. A new class of apps is offering more sophisticated mental health help to struggling teens, including emergency, 24/7 connection to counselors. Ted S. Warren/AP hide caption

itoggle caption Ted S. Warren/AP

David Adam is a writer and editor at the journal Nature and was a special correspondent at the Guardian, writing about science, medicine and the environment. Courtesy of Farrar, Straus and Giroux, LLC hide caption

itoggle caption Courtesy of Farrar, Straus and Giroux, LLC

By measuring activity in different parts of the brain, neuroscientsts can get a sense of how some people will respond to treatments. John Lund/Getty Images hide caption

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U.S. soldiers at Long Binh base in South Vietnam line up to give urine samples at a heroin detection center before departing for the United States. About 20 percent of soldiers said they were addicts, but most didn't continue drug use back home. AP hide caption

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