Is it possible that young adults and teenagers or adolescents can possibly get mental or brain disorders that signifigantly affect their cognitive functioning such as dementing diseases known as dementia. I am a young adult experiencing very troubling symptoms that often disable my thinking or thought processing which inhibits, distracts, and disrupts my capability to function normally on own. Is it possible that i have dementia or some serious neurological impairment. I am 19 years old.