We hear a lot about zombies these days – in films, in music and even in philosophy – but many are unaware that in 1997 The Lancet published a medical study of three genuine Haitian zombies.

The cases studies were reported by British anthropologist Roland Littlewood and Haitian doctor Chavannes Douyon and concerned three individuals identified as zombies after they had apparently passed away.

The Haitian explanation for how zombies are created involves the distinction between different elements of the human being – including the body, the gwobon anj (the animating principle) and the ti-bon anj, which represents something akin to agency, awareness, and memory.

In line with these beliefs is the fact that awareness and agency can be split off from the human being – and can be captured and stored in a bottle by a bòkò, a type of magician and spirit worker who can be paid to send curses or help individuals achieve their aims.

This purportedly leaves a passive easily-controlled animated body – the zombie – believed to be created to provide free labour on plantations.

Anthropologist Wade Davis claimed to have identified the ingredients of the bòkò’s zombification powder which supposedly included tetrodotoxin – a naturally occurring neurotoxin found in some animals, like the pufferfish, which can cause temporary coma-like states.

I won’t say much more about the ‘neurotoxin’ theory of zombification, not least because it was brilliantly covered by science writer Mo Costandi and I couldn’t improve on his fantastic article which will tell you everything you need to know.

But on the cultural level, zombies are identified by specific characteristics – they cannot lift up their heads, have a nasal intonation, a fixed staring expression, they carry repeated purposeless actions and have limited and repetitive speech.

This means that they are easily identified by the community and Littlewood and Douyon’s study was a medical investigation into three ‘returned zombies’ – each of which was identified as a member of the family who had died and who had returned with the characteristic features.

FI was a 30-year-old woman who had died after a short illness and was buried next to the house, only for her to be recognised in a zombified state three years later by her family, wandering near to her village.

WD died at the age of 18 shortly after his “eyes turned yellow” and his body “swelled up” and was buried in a family tomb. He was identified as a zombie at a cockfight eight years after he had been buried.

MM was a young woman who also died at 18 after a short illness, but who was identified 13 years later in the town market, walking around in the characteristic detached shambling way.

While the families put their fate down to sorcery, a full medical examination was carried out by the two doctors, including the use of EEG and CT brain scans.

FI showed no neurological damage but was diagnosed with catatonic schizophrenia, a very withdrawn form of psychosis. WD was found to have brain damage, probably from lack of oxygen, and epilepsy, which could be treated with drugs. MM was found to a developmental learning disability, probably caused by her alcoholism when her mother was pregnant with her.

The fact that doctors gave medical explanations for people identified as zombies is, perhaps, no big surprise, but most interesting was that DNA and fingerprinting tests that showed that two of the zombies were cases of mistaken identity. They weren’t the dead relatives that the families thought they were.

The authors of the study noted that it is unlikely that there is a single explanation for all people identified as zombies and there was a hint that the ‘neurotoxin’ theory could explain some cases. Two types of ‘zombification’ powder from local bòkòs were tested, and, in line with Wade Davis’s ideas, tetrodotoxin was found.

But more probable is that most cases are mistaken identification of wandering mentally ill or neurologically impaired strangers by bereaved relatives.

They noted “People with a chronic schizophrenic illness, brain damage, or learning disability are not uncommonly met with wandering in Haiti, and they would be particularly likely to be identified as lacking volition and memory which are characteristics of a zombi.”

Interestingly, the first known photograph of a zombie, shown above, was taken by anthropologist Zora Neale Hurston and reproduced in her 1938 book Voodoo Gods where it notes that the subject was photographed in a psychiatric hospital, which makes more sense in light of this more recent medical examination.

It’s worth making a final point that while zombies are a particularly well-known aspect of Haitian culture, thanks to the stereotypes and Hollywood hijacking, traditional Haitian psychology and related concepts of illness are hugely fascinating topics in themselves.

If you want to lose yourself in another understanding of ourselves and the world, you could do much worse than reading the World Health Organisation’s short report ‘Culture and Mental Health in Haiti’ which is available online as a pdf. The whole report is fascinating but start at the section on ‘Religion’ from page 6 if you want to get straight to the psychology.



Link to locked case study in The Lancet.

Link to Mo Costandi’s “The ethnobiology of voodoo zombification”.

pdf of WHO report on ‘Culture and Mental Health in Haiti’.