It's hard to even list them all because 'A Little Life' is basically a masterclass in emotional devastation, and I think that's a necessary starting point. If someone is looking for a light read or even a standard literary drama, they should run. The book deals with graphic, prolonged depictions of childhood sexual abuse and physical torture, which form the core of the protagonist's trauma. That's the big one, and it's not implied or off-page—it's described in detail. There's also extreme self-harm, suicidal ideation and attempts, drug addiction, and eating disorders presented in a very visceral way. The narrative doesn't shy away from the physical reality of the injuries and the psychological fallout.
Beyond that, I'd add warnings for emotional abuse, gaslighting, and manipulative relationships that persist into adulthood. The friendship circle is loving but often feels helpless, which can be its own kind of painful to read. There's also a significant element of internalized homophobia and the trauma surrounding identity. What makes the book particularly intense is the relentlessness; it's nearly 800 pages of cycling through these traumas with very few moments of genuine, lasting relief. It's not a book about recovery in a linear sense. The ending is... definitive and tragic. Honestly, the trigger warning should almost be for existential despair. I appreciated the book's craft, but I can't recommend it without serious caveats—it feels less like a story and more like an emotional endurance test.