A service animal can change the life of someone living with PTSD. A service animal is specially trained to do tasks that help mediate the symptoms of a disability. Below are some organizations that help people find a service animal. 
Paws4people Foundation

https://paws4people.org

Specializes in dogs for: children and adolescents with physical, neurological, psychiatric, and/or emotional disabilities; and Veterans and Service Members with Chronic/Complex Post-Traumatic Stress Disorder (C-PTSD), Traumatic Brain Injuries (TBI), and Military Sexual Trauma.

Paws For Veterans

http://www.pawsforveterans.com

Specializes in dogs for: Veterans

The Tower of Hope

http://thetowerofhope.org

Specializes in dogs for: disabled veterans and others in need of physical and psychological support