Michael Ziffra, MD, psychiatrist at Northwestern Memorial Hospital specializes in Post Traumatic Stress Disorder (PTSD). According to the National Institute of Mental Health, PTSD is a disorder that develops in some people who have experienced a shocking, scary or dangerous event. Lady Gaga recently revealed during her visit at a LGBT homeless shelter in Harlem, that she suffers from PTSD after being raped when she was 19 years old.

"I don't have the same kind of issues that you have," she said, "but I have a mental illness and I struggle with that every day so I need my mantra to help keep me relaxed."

Ziffra can discuss how sexual assault can trigger PTSD as well as the signs and symptoms to watch out for in people suffering with the condition.

Ziffra is board certified psychiatry at Northwestern Memorial Hospital and an assistant professor in psychiatry and behavioral sciences at Northwestern University's Feinberg School of Medicine.