He calls himself a friend, but one of the things Ed Gass-Donnelly did to his poor friend Abbie Cornish was stick her on a huge spit, the bastard. “We called it the car rotisserie,” says the filmmaker, with an evil chuckle, talking to the Straight at the Sutton Place Hotel during the Vancouver International Film Festival. He pulls up an iPhone video of the diabolical contraption his effects people built: a car that spins on a horizontal axis so that Gass-Donnelly could keep his camera locked on Cornish as her SUV does multiple rolls across a highway.

It provided the director with one of the many eye-popping set pieces in his new film Lavender, a visually rich psychological thriller screening on Saturday (October 8). When he sent the same iPhone video to his star prior to filming, he recalls, “I got a series of all-caps texts that basically just said, ‘FUCK NO!’ ” Thankfully, Ms. Cornish came around.

Lavender comes to Vancouver as part of this year’s ever-memorable Altered States series. This is where VIFF enters the after-dark realm of transgressive subject matter, genre extremes, or—in the case of Mexico’s demented We Are the Flesh (October 8 and 14)—genitals in extreme close-up. Lavender doesn’t aspire to that kind of shock value, but it does bring a hallucinatory focus to the uncomfortable topics of child abuse, trauma, and memory.

The Eyes of My Mother (October 7 and 13) covers similar ground as it spans the short distance from childhood trauma to child psychopathy, but with a heavily realized feel for the grotesque that first-time director Nicolas Pesce projects onto a starkly rendered black-and-white version of rural America. It’s an excruciating experience, or a thrilling one, depending on your tolerance for unthinkable matters including babies in peril and extended torture.

From the wider margins of American indie film, Zach Clark’s Little Sister (October 6 and 8) offers a bit more light and a few good yucks. As a goth turned nun, Addison Timlin competes with Ally Sheedy for the film’s best performance, the latter going for broke as her bipolar mom (while suggesting, perhaps, one possible future for the weirdo kid she played in The Breakfast Club). Ultimately, the film offers a sober and compassionate view of two generations brutalized by the empty promises of modern life, or worse—as represented by Keith Poulson’s hideously scarred Iraq war vet—by its increasingly insane demands.

In previous years, Altered States has tested enthusiastic midnight crowds with aspiring cult raves like Green Room, It Follows, and A Field in England. Its tendency is to grapple with modern anxieties in heightened ways—Operation Avalanche (October 10) goofs around with moon-landing-hoax conspiracies while buzzing with a legitimate distrust of authority—but it’s also a crucible for passionate and highly engaged filmmaking.

Indeed, as Gass-Donnelly reveals, he spent 10 years pondering “why I was interested and what I wanted to do with it”, after encountering an early draft of Colin Frizzell’s script for Lavender. “Of anything I’ve done, it was the slowest project,” he says. “I don’t even know if I can call it organic. It was like a slug slowly making its way into another shape.”

For more info on the Vancouver International Film Festival series Altered States, go to www.viff.org/.