Frank Heffley Schizophrenia is a series of TikTok edits and shitposts built around the fan theory that Frank Heffley, the dad from the Diary of a Wimpy Kid movies played by Steve Zahn, is schizophrenic, a psychopath, or an outright serial killer1. Most of the edits look nearly identical, grainy, black-and-white, and stitched from scenes where Steve Zahn's Frank already reads as unhinged, with the visual style borrowed from creepypasta, brainrot, and lobotomy-core TikTok4. Recycled quotes include "I knew that door had a lock on it," "What was General Grant doing on the thermostat?" and "Who's the laugher now?"1.

The trend hit TikTok en masse in March 2025 and drew comparisons to SueTok, another edit format that mangled clips of Sue Heck from The Middle before crawling to other Heck family members like Brick4. The Frank Heffley Schizophrenia label lumps together the horror-cut edits, the schizoposting captions, and the loose fan theory that the character was mentally ill the whole time.

A typical Frank Heffley Schizophrenia edit grabs a short clip of Steve Zahn yelling or looking manic in a Diary of a Wimpy Kid film, desaturates it, piles on grain, sometimes blows out the audio, and layers a horror or lobotomy-style track underneath1. Creators often stitch several unrelated Frank Heffley moments back to back so it looks like the character is spiraling in real time. The #horrortok tag and quotes like "I knew that door had a lock on it" are common conventions inside the format1.