Hektoen International

A Journal of Medical Humanities

Of Mice and Men: a differential diagnosis for Lennie Small

Howard Fischer
Uppsala, Sweden


Lennie from of Of Mice and Men
Colin Waters stars as Lennie in Charleston Stage’s 2018 production of Of Mice and Men. Photo courtesy of Marybeth Clark. Source.

In John Steinbeck’s 1937 novel Of Mice and Men,1 the two main characters work as itinerant laborers on farms and ranches in California during the Great Depression. Their only attachments are to each other. George is “small and quick” with “sharp, strong features,” while his companion, Lennie, is “a huge man, shapeless of face . . . with wide sloping shoulders who walked heavily, dragging his feet a little . . . His arms did not swing at his sides, but hung loosely.”

After orphaned Lennie’s Aunt Clara died, George decided to be a sort of guardian for him. Lennie is intellectually handicapped, has a poor memory, and is impulsive. His impulsivity leads him to do “bad things” and get into trouble.

These three major characteristics of Lennie—his size, his intellectual deficits, and his behavioral problems may serve as clues to possible diagnoses of his condition. Lennie is described as tall (“huge”), which is clinically defined as height greater than the 97th percentile for age and gender,2 and is divided diagnostically into proportionate and disproportionate tall stature.3,4 Those with disproportionate tall stature have an arm span, (arms extended outward like the wings of a plane) greater than their height, and the lower half of their body is longer than the upper half. Simply put, disproportionate tall stature means having very long arms and legs. There is no suggestion in the novel that Lennie is disproportionate in his stature, so certain conditions that include this physical feature: Marfan syndrome; 47, XXY (Klinefelter) syndrome; Beckwith-Wiedemann syndrome; and XYY syndrome are excluded.5

Conditions with proportionate tall stature include cerebral gigantism (Sotos syndrome) and Weaver syndrome.6 Adult males with Sotos syndrome average six feet (183 cm) in height, although there are at least two reports of men with this condition that were more than seven feet (213 cm) tall.7 People with Sotos syndrome also have a prominent forehead, jaw, and ears, large hands and feet, below-average intelligence (in 97%), and speech problems. They are described as being clumsy and having an awkward gait and about half of those affected have seizures.8 Sotos syndrome is associated with a deletion in the NSD1 gene.9

Weaver syndrome, another condition with proportionate tall stature, includes typical facial features, hand deformities as well as intellectual deficits in 80% of individuals.10

An intellectual disability (formerly called mental retardation) consists of below average intelligence and deficits in two or more adaptive behaviors appropriate for age: self-care, home living, communication, self-direction, and attention to safety. The disability is mild in about 85% of the intellectually handicapped population, which corresponds to an adult having a mental age of about 9-11 years. A moderate intellectual disability corresponds to an adult having a mental age somewhere between 6-8 years, or an IQ below 50 or 55, with 100 being the average for the general population.11

In autism or autistic spectrum disorders, language and reciprocal social behaviors are more affected than nonverbal reasoning skills. These people may have a narrow repertoire of interests and behaviors, repetitive actions, and echolalia.12 They may have a sensory attraction to soft things such as fur or velvet, and react to sensory overload (noise, for example) with “meltdown” behavior—a complete and involuntary loss of behavioral control.13

It is estimated that about 70% of persons with autistic spectrum disorders also have some degree of intellectual handicap.14

Diagnosing a fictional character like Lennie Small is tricky. We have no medical history concerning his family, birth, childhood, or early adulthood. There are physical and behavioral descriptions in the book, but no clinical observations or standardized tests.

Based on what Steinbeck has written I believe that Lennie most likely had Sotos syndrome. We have no reason to think that his tall stature is disproportionate, and although Lennie was taller than average for those affected with Sotos syndrome, there are reports in the medical literature of adult men with the condition who are more than seven feet tall. Sotos syndrome includes intellectual deficits, which are mild in about 30%, moderate in 45%, and severe in 20%.15 Lennie likes to pet soft things, and in the novel he accidentally kills a pet mouse, and a puppy, by stroking their soft fur too forcefully. He ultimately kills a woman who has invited him to stroke her hair. When the stroking becomes too rough, the woman panics and starts to scream. Lennie has a meltdown, does not let her go, and finally suffocates her because of the screaming. This is the worst of the “bad things” he has ever done.

Some authors have suggested other diagnostic possibilities. Ledesma16 writes that Lennie’s meltdowns are actually panic attacks. Panic attacks, however, may occur suddenly and unexpectedly, without a triggering event, and are accompanied by a number of somatic signs and symptoms, that are not described in the story. Watanabe17 proposes that Lennie is “Lennie Small” because Steinbeck wants to tell the reader that Lennie is subject to petit mal attacks of epilepsy. Very few people with Sotos syndrome have these absence (petit mal) seizures,18 and autistic meltdown represents a more likely possibility.

“Ockham’s razor,” suggests that the simplest explanation, using the fewest assumptions, is usually the best explanation. Sotos syndrome would account for Lennie’s physical appearance as well as his intellectual deficit. It is reasonable to suggest that an autistic spectrum disorder is also part of his condition.

Was Lennie modeled on someone Steinbeck knew, a composite of characteristics of several individuals, or a totally imaginary representation of strength, bad judgment, and poor impulse control? Steinbeck answered this in an interview with the New York Times in December 1937.19 “Lennie was a real person. He’s in an insane asylum in California right now. I worked alongside him for many weeks. He didn’t kill a girl. He killed a ranch foreman. Got sore because the foreman fired his pal and stuck a pitchfork right through his stomach . . . I saw him do it. We couldn’t stop him until it was too late.”

More than eighty years have passed since Of Mice and Men was written. One can only hope that today the fate of a man like Lennie would be very different. Modifications in social environment and adaptive education can help people like Lennie to live more successfully in society, although society itself still needs to better learn how to adapt to those with physical and cognitive differences.



  1. John Steinbeck. Of Mice and Men/Cannery Row. New York: Penguin Books, 1949.
  2. Pinchas Cohen and Melanie Shim, 2007. “Tall Stature,” In Nelson Textbook of Pediatrics 18th ed, RM Kliegman et al, 2304-2307. Philadelphia: Saunders.
  3. Christina Meazza, Chiara Gertosio, Roberto Gincchero, Sara Pagani, and Mauro Bozolla, “Tall Stature: A Difficult Diagnosis?”, Ital J Ped, 43, no.6, 2017.
  4. Justin Davies and Tom Cheetham, “Investigation and Management of Tall Stature,” Arch Dis Child, 99, no. 8, 2014.
  5. Davies and Cheetham, “Investigation.”
  6. Davies and Cheetham, “Investigation.”
  7. Steinbeck, “Of Mice.”
  8. Steinbeck,” Of Mice.”
  9. Davies and Cheetham, “Investigation.”
  10. Meazza, “Tall stature,”
  11. Bruce K Shapiro and Mark L Batshaw, 2007. “Mental Retardation (Intellectual Disability),” In Nelson Textbook of Pediatrics 18th ed, RM Kliegman et al, 191-197. Philadelphia: Saunders.
  12. Eric M Butter and James A Mulick, 2009. “Autism,” In American Academy of Pediatrics Textbook of Pediatric Care, TK McInerny et al, eds. 1196-1201. Elk Grove Village, IL: American Academy of Pediatrics
  13. Clare Lawrence, “Is Lennie a Monster? A Reconsideration of Steinbeck’s Of Mice and Men in a 21st Century Inclusive Classroom Context,” Palgrave Commun, 6, no. 17, 2020.
  14. Butter and Mulick, “Autism.”
  15. Andrew Edmonson and Jennifer Kalish, “Overgrowth Syndromes,” J Pediatr Genet, 4, no.3, 2015.
  16. Jillian Ledesma, “Diagnosing Lennie Small,” In Project Muse—Intellectual Disability in Carlisle Floyd’s “Of mice and Men,” 2016
  17. Nancy Ann Watanabe, “Medical Genetics and Steinbeck’s Of Mice and Men,” https://www.researchgate.net/publications/341844984
  18. Francesco Nicita, Martino Ruggieri, Agata Polizzi, Laura Mauceri, Vincenzo Salpietro, Silvana Briuglia, Laura Papetti, et al, “Seizures and Epilepsy in Sotos Syndrome: Analysis of 19 Caucasian Patients with Long-term Follow-up,” Epilepsia, 56, no.6, 2012.
  19. Thomas Fensch, ed. Conversations with John Steinbeck. Jackson: University Press of Mississippi, 1988.



HOWARD FISCHER, MD, retired as a professor of pediatrics from Wayne State University School of Medicine, Detroit, Michigan. He spent much of his career diagnosing and treating child abuse and neglect. He has always been interested in the relationship between literature and medicine.


Winter 2021  |   Sections  |  Literary Essays

One response

  1. It is possible he had Beckwith-Wiedemann syndrome, my son has it and is proportional.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.