The Salem Witch Trials: If not witchcraft, then what?

January 20th, 2026

Written by: Emma Fischer

Among one of the spookier (and most intriguing) chapters of American history is the story of the Salem Witch Trials. From 1692 to 1693, over 200 people around Salem, Massachusetts were accused of witchcraft, with over 20 of them being sentenced to death.¹ The trials began when two young girls, Betty Parris and Abigail Williams, reported painful sensations and showed symptoms including hallucinations and contortion of their bodies.² The community responded by accusing three local women of practicing witchcraft to cause these symptoms, and the Salem Witch Trials began.

Many factors likely fueled these accusations and contributed to the paranoia that took over Salem. Some researchers have suggested that historical and societal factors like neighborhood feuds, stress, and mass hysteria may have contributed to the frenzy of witchcraft accusations. However, these explanations often focus on the reasoning behind the widespread accusations of witchcraft. If not witchcraft, what might have caused the “afflicted” victims of witchcraft to display such symptoms? Here, we’ll consider the medical explanations that might really have caused the afflicted to experience their symptoms and how they impact the brain.

Possibility #1: Ergot poisoning

One medically-based explanation for the behavior of the afflicted in Salem is that those individuals were experiencing ergot poisoning.³ Ergot is a fungus that infects rye and other grains that are commonly used to make bread, and produces molecules called alkaloids that interact with the brain and nervous system.⁴ The interaction that would lead to the symptoms seen in the afflicted of Salem involves a neurotransmitter (a chemical signaling molecule in the nervous system) that plays a role in your emotions and in cognition in general, called serotonin. Exposure to these infected grains can give the ergot alkaloids access to the brain, where they can mimic the effects of releasing serotonin, which triggers more activity in the brain than normal. This “serotonin” overload can be toxic, overactivating parts of the body and brain more than normal. This can lead to adverse reactions across the whole body, including muscle twitching and tremors as well as confusion.⁵

The symptoms of ergot poisoning can include hallucinations, paranoia, and seizures, which match what Betty Parris and Abigail Williams were experiencing.³ If, for example, an individual ate bread made from rye contaminated by ergot, the person might act in a way that seems, well, bewitched. Interestingly, ergot contains similar compounds as LSD, which can also cause hallucinations. While ergot poisoning may seem like the clear explanation, some historians argue that there are crucial differences between this and the behavior of the afflicted. Ergot poisoning also causes vertigo, vomiting, and other symptoms that were not present in Salem.⁶ Further, eating contaminated bread would likely have affected an entire household rather than a handful of individuals, making this theory an unlikely culprit.⁶

Possibility #2: Anti-NMDAR encephalitis 

An explanation for the symptoms of the afflicted that has become more popular in the past decade is anti-NMDAR encephalitis.⁷ Anti-NMDAR encephalitis is a type of autoimmune encephalitis where the immune system gets its wires crossed and tells the body to start attacking itself.⁸ This causes inflammation, or swelling, in the brain, leading to negative and potentially life-threatening symptoms. NMDAR, or NMDA receptors, are neurotransmitter receptors located on neurons that play a crucial role in proper nervous system function, including in learning and memory and synaptic plasticity. In anti-NMDAR encephalitis, antibodies flag NMDA receptors as harmful, and these receptors are removed from their location on a neuron, which prevents those cells from functioning normally.⁹ When the neuron function is disrupted, cognition becomes impaired, behavior changes, and seizures and hallucinations can occur.⁹ 

The symptoms of anti-NMDAR encephalitis map well with what was observed in the cases of Betty Parris and Abigail Williams: the erratic movement and behavior exhibited by the girls could be explained by the effects of this disorder. Additionally, in modern anti-NMDAR encephalitis cases, patients exhibit involuntary contortion of the body, anxiety, and impaired speech, among other symptoms.⁸ With such strong parallels, it’s no surprise that this disorder has been tied to the bewitching of Salem.

It’s certainly possible that a few people, particularly the initially-afflicted individuals, may have been affected by one of these diseases. However, it’s unlikely that enough people in Salem were actually afflicted by either of these diseases to justify the accusations of witchcraft of over 200 individuals. These accusations likely stemmed more from a combination of social and historical factors like stress, interpersonal conflict, and Puritan societal values than a community-wide affliction with one of these medical conditions. Although each of the proposed medical theories is flawed and we can never truly determine the cause of the paranoia that tightly gripped the Salem community, blending science with history (and the supernatural) to offer explanations for these events always proves interesting. 

References

1. Baker, E. W. (2016). The Salem Witch Trials. In Oxford Research Encyclopedia of American History.
2. Hale, J. (2006). Modest Enquiry into the Nature of Witchcraft. Applewood Books.
3. Caporael, L. R. (1976). Ergotism: The Satan Loosed in Salem? Convulsive ergotism may have been a physiological basis for the Salem witchcraft crisis in 1692. Science, 192(4234), 21-26.
4. Haarmann, T., Rolke, Y., Giesbert, S., & Tudzynski, P. (2009). Ergot: from witchcraft to biotechnology. Molecular Plant Pathology, 10(4), 563-577.
5. Eadie, M. J. (2003). Convulsive ergotism: epidemics of the serotonin syndrome?. The lancet neurology, 2(7), 429-434.
6. Spanos, N. P., & Gottlieb, J. (1976). Ergotism and the Salem Village Witch Trials: Records of the events of 1692 do not support the hypothesis that ergot poisoning was involved. Science, 194(4272), 1390-1394.
7. Tam, J., & Zandi, M. S. (2017). The witchcraft of encephalitis in Salem. Journal of Neurology, 264(7), 1529-1531.
8. Dalmau, J., Lancaster, E., Martinez-Hernandez, E., Rosenfeld, M. R., & Balice-Gordon, R. (2011). Clinical experience and laboratory investigations in patients with anti-NMDAR encephalitis. The Lancet Neurology, 10(1), 63-74.
9. Lynch, D. R., Rattelle, A., Dong, Y. N., Roslin, K., Gleichman, A. J., & Panzer, J. A. (2018). Anti-NMDA receptor encephalitis: clinical features and basic mechanisms. Advances in Pharmacology, 82, 235-260.

Cover photo from Freepik on Freepik.