A question kept running through my head as I watched The Substance, an outrageous and beyond bizarre horror film that had its North American premiere at the Toronto International Film Festival on Thursday night.

What is wrong with these people?!

Our judgment begins with the damaged or disturbed characters.

Elisabeth Sparkle, played to perfection by Demi Moore (what is wrong with her?!), is an Oscar-winning actress turned fitness guru à la Suzanne Somers, whose luxurious Hollywood home is hung with enormous portraits of her in her prime.

After Elisabeth is abruptly fired from her TV job “Sparkle With Elizabeth,” the disillusioned actress learns of an underground drug called “Substance” that promises to create a younger, more attractive doppelgänger of a person. Elisabeth, a real-life California narcissist, immediately signs up.

At this point we begin to wonder what is wrong with the hugely talented and creative screenwriter and director Coralie Fargeat, from whose French nightmares this amazing film undoubtedly springs.

When Elisabeth injects herself with the plutonium-green substance, her back splits open in a bloody manner and her seductive clone jumps out like a xenomorph in “Alien.”

The only unbreakable rule, with dire consequences, is that the young counterpart is only allowed to walk the earth for seven days at a time – while Elizabeth hibernates – before they swap places again.

Almost immediately, Liz’s piggish former boss (Dennis Quaid at his funniest) hires the beautiful clone who calls herself Sue to be his hot new workout show host of a show called “Pump It Up.”

When Elisabeth wakes up, she is mocked by billboards and posters featuring Sue and develops a love-hate relationship with her popular counterpart.

Moore, at her best and often naked, delivers one of her best performances in years, transforming from It Girl to Gollum in over two hours. Impeccable makeup and prosthetics help, but the real horror comes from beneath the surface.

Qualley, on the other hand, spends most of the film smiling and crouching – never in a boring way, mind you – but behind this shiny facade lies budding resentment and darkness.

Opportunist Sue, after seven days, would rather not take a week-long nap and will resort to harmful extremes to stay awake. (There’s definitely something wrong with her.)

This leads to a Grand Guignol finale that is so strange, twisted and comical that we can only marvel that the investors actually said, “Sure, we’ll pay for that.”

As far as the audience is concerned, something is wrong with us too.

I enjoyed this rollercoaster ride of excitement, agony, madness and exploitation so immensely that I considered enrolling in online therapy to cope.

Maybe that’s because The Substance, as staggeringly weird as it is, is part of a grand, kitschy tradition. It’s the hotter, younger offshoot of Death Becomes Her and, set in a jealous two-woman LA household, even Whatever Ever Happened to Baby Jane?

In the end it is “Frankenstein” And “Young Frankenstein.”

What makes Fargeat’s film stand out from others – and sends some viewers running to the bathroom – are the body horror elements.

Their film is provocative, cruel, bloody and, to some, repulsive, and it will generate hugely controversial debate when it hits theaters later this month.

Similar to the title drug, it is difficult to recommend it generally without listing a multitude of side effects.

However, there is nothing wrong with limitless creativity, epic visions and a little gonzo entertainment in the cinema these days.

And by the way, there’s even a bit of substance in his clever parody of our youth-obsessed culture.