Perhaps only an Iraq War combat vet would dare to tackle Post Traumatic Stress Disorder with the sort of sarcasm and gallows humor of “My Dead Friend Zoe.”

Director and co-writer and ex-paratrooper Kyle Hausmann-Stokes’ film’s title character is a cynical smart-ass, a female veteran and a ghost. Zoe is, as advertised, “Dead.”

Zoe, given just enough edge by Natalie Morales, has the license to call her service in Afghanistan “the dumbest war of all time,” the sass to suggest she and her fellow GI trooper/ mechanic Merit (Sonequa Martin-Green) “watch ‘M*A*S*H’ again,” but this time not “as a drinking game” and the impatience to refer to the group therapy they attend back home as “kumbaya” nonsense.

But Merit is the one physically there at therapy. Dead Zoe is the snide commentator in her head and the ongoing presence in her life, and the most important thing Merit won’t talk about in “group,” no matter how much the doctor and Vietnam vet in charge (Morgan Freeman) demands it.

“My Dead Friend” is a nice showcase for constantly-employed TV actress Morales (“Parks and Rec,” Grey’s Anatomy,” “The Morning Show”). But it’s a star vehicle for “Walking Dead” alumna and “Star Trek: Discovery” lead Martin-Green.

It is Merit who must hide the “dead” friend she still communes with, among other unspoken traumas of her service. She does this while in court-ordered group therapy, something that’s interrupted when she has to care for her testy, “wandering” and increasingly forgetful grandfather and role model, a retired Lt. Col. played by Ed Harris.

That tells us this script is deep enough to attract talent, even as it gives Zoe and Merit Rihanna sing-alongs at work, even as Zoe serves up therapy-is-for-thee-but-not-for-me tough gal sarcasm softballs, even as she’s mocking Merit’s home state.

“Isn’t Oregon known for its serial killers?”

Freeman, who is as empathetic as he’s ever been on screen and the tightly-wound side of Harris lend the picture extra gravitas. But none of this would work if Martin-Green didn’t have the bearing of a soldier, one who has seen and experienced things. Compulsive jogging and visits to a cemetery are Merit’s coping mechanisms.

Introducing a possible love interest (“Pitch Perfect” alumnus Utkarsh Ambudkar) doesn’t add much that feels necessary, when layers of the Merit-Zoe connection and disconnection are left hanging. But even these mysteries benefit the film as we can infer “this” and understand without knowing “that.”

And Freeman’s doctor gives voice to talking therapy’s one essential truth in facing the many shades of PTSD, that one must “think very seriously about whether living in the past is worth it.”

Stay through the credits if you want to see how important this subject is, with or without jokes only those who’ve been through it truly “get.”

Rating: R, combat stress subject matter, profanity

Cast: Sonequa Martin-Green, Natalie Morales, Ed Harris, Gloria Ruben, Utkarsh Ambudkar and Morgan Freeman

Credits: Directed by Kyle Hausmann-Stokes, scripted by Kyle Hausmann-Stokes and A.J. Bermudez. A Briarcliffe release.

Running time: 1:38