A 35-Year-Old Male Combat Veteran Presents with Symptoms of Poor

A 35-year-old male combat veteran presents with symptoms of poor sleep, crying episodes, flashbacks, and nightmares. He also reports his marriage and friendships have been suffering, in addition to poor work performance. When in a bad mood, he tends to smoke cigarettes and drink alcohol. He has tried to overcome these symptoms on his own, but has been largely unsuccessful and now recognizes the need for professional help. He speaks openly about his experiences and recognizes a direct connection between his combat exposure and current symptoms. Which of the following would be the most likely diagnosis?

A) Panic disorder
B) Obsessive compulsive disorder
C) Autism spectrum disorder
D) Posttraumatic stress disorder