A widow deceives her late husband's mother and brothers into thinking he's still alive when she attends the yearly memorial to his drowned sister, hoping to secure his inheritance, but her cunning is no match for the demented, axe-wielding thing roaming the grounds of the family's Irish estate.
Unfortunately the movie Dementia 13 is not yet available on HBO Max.
| Directing | Francis Ford Coppola | Director |
| Writing | Francis Ford Coppola | Writer |
| Production | Roger Corman | Producer |
| Crew | Patrick Doyle | Other |
| Art | Paul Julian | Title Designer |
| Crew | Jack Hill | Additional Writing |
| Art | Eleanor Coppola | Set Supervisor |
| Crew | George Brady | Other |
| Camera | John Vicario | Camera Operator |
| Production | Eyemonn Callian | Production Assistant |
| Crew | Michael Purcell | Other |
| Crew | Patrick Brady | Other |
| Camera | Michael Vines | Best Boy Grip |
| Crew | William Joseph Bryan | Technical Advisor |
| Crew | Francis Ford Coppola | Stunts |
| Editing | Stuart O'Brien | Editor |
| Camera | Charles Hannawalt | Director of Photography |
| Editing | Morton Tubor | Editor |
| Directing | Richard F. Dalton | Assistant Director |
| Editing | Donald Shebib | Assistant Editor |
| Production | Marianne Wood | Associate Producer |
| Art | Al Locatelli | Art Direction |
| Directing | Jack Hill | Second Unit Director |
| Directing | Angela Wadlow | Script Supervisor |
| Art | Edward Delaney | Sculptor |
| Sound | Liam Saurin | Sound |
| Sound | Joseph Gross | Sound |
| Sound | Ronald Stein | Original Music Composer |
