‘My Friend Dahmer’ goes to high school with the serial killer

Even serial killers were children once, and it must be a trip to realize later on that you grew up alongside one. Especially if that childhood chum-turned-murderer turned out to be Jeffrey Dahmer.

That was the unreal situation cartoonist John “Derf” Backderf found himself in when Dahmer was arrested for the rape, murder and mutilation of 17 people, many involving necrophilia and cannibalism. His autobiographical 2012 graphic novel “My Friend Dahmer” captures that weirdness as he recounts their high-school years together and, with the benefit of hindsight, zeroes in on the many warning signs.

The film adaptation (first seen in Chicago in November and returning Friday at the Gene Siskel Film Center) is a good one, and largely faithful, as it plumbs Dahmer’s dysfunctional home life for explanations without making excuses. It excels at capturing the era, getting not just the 1970s fashion and wood-paneled interiors right, but the kind of hands-off parenting and schooling that would allow someone as fundamentally broken as Dahmer to fall so easily through the cracks.

By all appearances, Dahmer (Ross Lynch) is your garden-variety outcast, terminally awkward and unsuited to the social trials of high school. He is all but invisible, hiding behind a mop of floppy blond hair and an enormous pair of glasses.

But in the background, things are already going desperately wrong. Borrowing chemicals from his chemist father, Dahmer has taken to spending long hours in a shed in the woods, dissolving roadkill in jars of acid and preserving bones. He has also formed an unhealthy obsession with a fit and personable doctor (Vincent Kartheiser), whose jogging schedule he has memorized.

His father expresses concern for his son’s well-being, but only in the brief intervals where he’s able to focus on anything other than his crumbling marriage. Dahmer’s mother Joyce (Anne Heche, in a bleakly comical performance) takes up most of the air in the house. A manic pill-popper, she has her own history of mental health problems – a UFO sighting and a stint in a psychiatric hospital is mentioned – and there is little room left to worry about the young Dahmer. It’s a dreary home life, and it’s easy to see how someone who is already miswired could twist further inward in its stifling air.

In his descent, Dahmer – impossibly – makes some friends. Affably nerdy Backderf (Alex Wolff) and his buddies take notice of Dahmer when he emerges from the shadows to play class clown, offensively imitating a man with palsy. It’s catnip to the teenage boys, and they adopt Dahmer, agent of chaos, as a sort of mascot.

The film makes a tactical error in abandoning the book’s vantage point. Here, Backderf is a supporting character, a doodling cartoonist who takes an occasional interest in the class weirdo. Instead, the story is largely told from Dahmer’s perspective, and we know too much about where he ends up to feel anything like sympathy for him.

It’s still a morbidly fascinating peek behind the blood-stained curtains. But less time spent staring into Dahmer’s expressionless face and more time spent with characters capable of empathy would have served “My Friend Dahmer” well.

Barbara VanDenburgh, USA TODAY Network

★★★

FilmRise presents a film written and directed by Marc Meyers. Rated R (for disturbing images, language, teen drug use, drinking and sexual content, and for brief nudity). Running time: 107 minutes. Opens Jan. 19 at the Gene Siskel Film Center.