Next time you're having an old friend for dinner, it might pay to check they're not easily humiliated - they might just have you for dinner instead.
Scientists looking at the history of a group of five pathological cannibals kept in a French psychiatric facility have found there are two main kinds.
- Russian cannibal couple claim to have killed up to 30 people
- 'Cannibal killer' shot dead by police while eating woman's body
The type you're probably familiar with from movies like The Silence of the Lambs suffer from "a mixed personality disorder with sadistic and psychopathic features associated with paraphilia".
According to the American Psychiatric Association, paraphilia is a "sexual desire or behaviour that involves another person's psychological distress, injury, or death, or a desire for sexual behaviours involving unwilling persons or persons unable to give legal consent".
The researchers said "ego and narcissism are the central issue, with a desire to overcome deep-rooted frustrations by means of an extraordinary act", in a paper published in the Journal of Forensic Science.
"Feelings of humiliation seem to be the trigger, and both patients assaulted their victims at a time when they suffered a loss of self-esteem."
The other group suffered severe schizophrenia, with cannibalism "a self-defence reaction to a perceived threat of destruction".
"Survival depends on the annihilation or assimilation of the other."
All five of the cannibals studied were men, so the findings might not apply to all cannibals, the researchers say. And each would have their own reasons for committing one of the ultimate taboos.
"While [background] of these patients may highlight the reasons behind their assault, the nature of the act remains a mystery."
CNN presenter Reza Aslan made headlines in 2017 when he ate cooked human brains whilst dining with extremist Hindus for an episode of his show Believer.