“My Friend Dahmer,” which released to a limited amount of theaters on Friday, follows the true story of Jeffrey Dahmer’s high school years, including his difficult family and school life, and ends with the beginning of his life as a notorious serial killer.

It’s during those teenage years that Dahmer, who is played by Ross Lynch on-screen, meet John “Derf” Backderf, portrayed in the film by Alex Wolff, and the two, along with a few others, begin a relationship that’s somewhere between friendship and bullying.

Years later, after Dahmer, who was incarcerated for murdering and raping over 15 men and boys, died in prison, the real-life Derf wrote about his time with Dahmer and released the story as a short graphic novel in 2002. He later released a full-length graphic novel in 2012, with both titled “My Friend Dahmer,” the eventual name of the film adaptation, as well.

While Dahmer and Derf are real people and the film is based off of a graphic memoir by Derf, how much of it is actually true and how much is fiction?

The names of Dahmer’s family - mom, Joyce, dad, Lionel and brother, Dave - and close schoolmate, Derf, in the film are all true. The scenes of Dahmer being drawn to dead animals, murder and decomposing dead animals in chemicals is all true, as Dahmer claimed that his compulsion towards these things began when he was 14.

The movie fact that his mom was once in a mental institution is actually true, as is the movie scene when Dahmer draws an outline of a dead body in a school classroom.

Also real was the dismantling of his family during high school when his parents got a divorce. This is seen in the movie as a huge turning point for Dahmer, who starts to act more withdrawn afterwards and who begins to slowly act out more of his thoughts than he had before. Besides giving into some of his darker thoughts, he also starts bringing alcohol to school and drinking a lot. This is all portrayed accurately.

The film includes more true storylines, including Dahmer fantasizing about hurting a male jogger and watching him day in and day out in the bushes until one day deciding to wait in the bushes with a bat to finally put his thoughts into action, only for the jogger to not show up that day.

The end of the film, when Dahmer picks up a hitchhiker and asks him if he wants a ride and if he wants to go drink a few beers, is also all real. This was how Dahmer found his first victim.

Since the film only covers Dahmer’s late high school years, and because it was based on Derf’s first-hand account, as well as knowledge of Dahmer the world already has, the film did a good job of including mostly facts about his life.

Except for one scene. In real life, during a school trip to Washington, D.C., Dahmer talked his way into getting himself, Derf and a few others into the Vice President’s office, though they were only able to briefly be there and see him from afar. In the film, the crew of students are actually able to meet the Vice President and talk to him for a bit about their life goals.

Besides this one scene, the only main other parts of fiction that the film had to add are the words spoken between characters and the everyday actions and activities, as those are necessary to fill the gaps.

“My Friend Dahmer” is now out in theaters