Sgt. Derrick Junge was diagnosed with a concussion, but passed over for a Purple Heart. Junge has not received rehabilitation or treatment for ongoing medical difficulties, and he struggles with simple tasks. NPR/Frontline hide caption

itoggle caption NPR/Frontline

The hallucinogenic compound found in psilocybin mushrooms like these is getting a fresh look as a medicine to help patients cope with terminal illness. Wikimedia Commons hide caption

itoggle caption Wikimedia Commons

Keeping an active mind by doing things like playing chess helps stave off the development of dementia. Bulent Kilic/AFP via Getty Images hide caption

itoggle caption Bulent Kilic/AFP via Getty Images