- The first lady's ill health, stormy moods led some to suggest insanity
- But a modern doctor and scholar believes she had pernicious anemia
(CNN)Historians have long been fascinated with the behavior of Mary Todd Lincoln.
She was one of the most interesting and polarizing first ladies of the 19th century: Her unusually stormy moods, coupled with rumors of delusions, constant headaches and pallor, have led historians to suggest that she was "insane," "hypochondriacal," "menstrual" and the "female wild cat of the age."
But a modern doctor and scholar, Dr. John Sotos, has a much more sympathetic take on her affliction. He believes she suffered from an ailment that probably would not have been diagnosed, an extremely common health problem in her time that is rare today.
After researching his new book and publishing a study in Perspectives in Biology and Medicine, Sotos wants to end the ailment argument once and for all.
Sotos, who was a medical technical adviser for the TV show "House M.D.," believes he has solved one of the great medical mysteries of American history.
Mary Todd Lincoln, a paradox
But before we share Sotos' professional medical opinion, you may be wondering why there is a debate about the health of a woman who hasn't been to the doctor in 150 years.
When it comes to her health, biographer Jean Baker describes her as "the reverse of Teflon."
"Every medical diagnosis has been postulated about her, it runs the gamut from Lyme disease to chronic fatigue to diabetes," said Baker, an award-winning historian at Goucher College.
Historians also often described Lincoln with a kind of misogynistic dismissiveness, Baker noted, chalking her symptoms up to "hysterical" female problems.
Sexism in the historical record aside, Lincoln is difficult to pin down because she seems to have two distinctly different personalities.
As a young woman, friends described her as having a "natural kindness of heart." She was well-educated, intensely intellectual and a gifted conversationalist at parties. As a partner, she was ambitious and politically astute, guiding her famously devoted husband, Abraham Lincoln, to become not merely the president but one of American history's most important.
But in the White House, she developed a bad rap for her terrible temper and sour disposition. Angry outbursts earned her the nickname "the hellcat" from the president's assistant private secretary. And, as one historian put it, regularly "she indulged in her orgies of buying things," like some kind of Victorian Imelda Marcos.
It's hard to blame anyone for needing at least a little retail therapy, if not becoming deeply depressed over her tragic public life.
She lost not one but three sons in her lifetime. In the White House fishbowl, the press constantly hounded her, and vicious gossips mocked her unflattering gowns, portraying her as a Confederate spy or a Western hick.
Her husband lived under constant threat, and she ultimately lost the love of her life when he was shot, sitting next to her, holding her hand in a theater as they watched a British farce about rube-ish Americans.
Late in life, her remaining son had her forcibly committed to an asylum, a humiliation she endured for three months before friends could spring her.
At her death, her doctor argued that society should not judge her harshly and chalked up her behavior to "cerebral disease."
But was it really mental illness that changed her personality so much?
The medical record
None of Lincoln's primary medical records exists today, with the exception of limited notes doctors kept when she was forcibly institutionalized. That's only four months of records.
Without lab tests or DNA, which provides only limited detail, Sotos is left with about 100 historic sources, including 678 letters and photos from the time.
In his book "The Mary Lincoln Mind-Body Sourcebook," Sotos argues that that record is enough. For those who might question this practice -- and some scholars do take issue with any retrospective diagnosis of an historical figure -- Sotos writes, "the amount of information in the historical record exceeds the amount a physician might collect in a 10-minute clinical visit -- a duration clearly sufficient to make many diagnosis."
He argues that only one thing can account for the many disparate mental and physical symptoms he finds described in the letters.
Sotos believes Lincoln suffered from pernicious anemia.
The dreaded 'Downton Abbey' disease
Pernicious anemia, which doctors sometimes call PA, has all but disappeared in modern life and from most modern medical literature.
Only "Downton Abbey" fans may recognize the disease as (spoiler alert) London doctors inaccurately diagnosed Lord Merton with it, initially causing much consternation. PA was a death sentence in the early 20th century, when the show took place, and was among the most common reasons for people to be hospitalized.
In Lincoln's time, it wasn't even a diagnosis. According to Sotos' research, PA was not known in English-language medical literature until 1874, eight years before Lincoln's death.
Sotos argues that nearly all of Lincoln's symptoms fit the description of PA as it progresses, if left untreated.
A severe vitamin B12 deficiency causes PA. Your body needs B12 to make red blood cells and nerves and to keep DNA functioning properly. People sometimes don't get enough because of their diet -- vegans are vulnerable -- or more often, the stomach wall stops making the chemical the body uses to absorb the vitamin from food.
It was deadly because doctors didn't know what caused it. No treatment surfaced until 1926, when three doctors -- George Whipple, George Minot and William Murphy -- demonstrated that PA patients who ate a half-pound of raw liver daily could be cured. It was such a big medical advance that the trio won the Nobel Prize in 1934.
When B12 was finally isolated in 1948, it enabled scientists to create a shot that people can get once a month and stay healthy.
PA, a slowly progressive disease, can account for the otherwise seemingly unconnected symptoms throughout Lincoln's life that got worse as she aged, Sotos argues.
Sotos lists Lincoln's symptoms over 30 years, which match PA symptoms, including a regular pallor to her skin, fever, headaches, gait problems, abnormal sensations as if she were being stuck by needles, soreness to her mouth, swelling, shortness of breath and resting tachycardia.
Psychologically, she started to show signs of hypervigilance, delusions and hallucinations, but all with a kind of perceived clarity. B12 deficiency shrinks the brain, leading to a significant decline in cognitive function, paranoia and hallucinations.
As she got older, the energetic woman who loved to read could no longer see well, and toward the end she became so weak and tired, she could barely move. Eventually, no longer able to speak, she communicated by blinking.
At her death, she was diagnosed with "a slight apoplexy," which seems to match the description of other PA deaths at the time, Sotos argues.
So what now?
Sotos hopes that this diagnosis will help future scholars reassess this "notoriously difficult-to-understand partner to one of the most consequential figures in world history."
Biographer Baker isn't totally sold. "I think it is great that he walked out on this speculative length," she said. But she said Lincoln was a "ball of fire," full of energy.
However, as a progressive disease, PA may not sap someone's energy right away.
Recently discovered letters suggest that Lincoln may have been taking too much chloral hydrate for sleep problems, which could account for some of her mental problems, Baker said.
Baker has said some scholarship suggests that Lincoln's symptoms may have been related to spinal stenosis or diabetes. Sotos has argued that those diseases couldn't totally account for her mental problems, but PA can be the cause of both mental and physical symptoms.
Ultimately, Baker said, with so many symptoms described in these letters as being "vague," they may be a good fit for many diagnosis.
Sotos is convinced and says the diagnosis has changed his own opinion of Lincoln.
He said he came across the first lady as he put together a book, "The Physical Lincoln," a medical analysis of Abraham Lincoln. Back then, when he made headlines for diagnosing the president with a rare genetic disorder, MEN2B, his research about Mary Todd Lincoln left him a critic.
"I came away not liking her at all," he said. But as he re-examined her record using the same medical style of research, his opinion softened.
"Once I made this diagnosis or at least started to entertain the idea, my attitude toward her changed," he said. "I think others will, too."