Over the centuries, many history buffs have speculated over the source of the erratic behavior of Abraham Lincoln's wife, Mary Todd Lincoln. The First Lady reportedly had extreme mood swings, engaged in manic shopping sprees, and experienced delusions and paranoia. Later in her life, Mary Todd Lincoln’s son briefly committed her to a mental hospital.

Today, physicians might attribute her symptoms to a psychiatric condition, like bipolar disorder, or a brain infection caused by syphilis. Meanwhile, others argue that she suffered from Lyme disease, chronic fatigue disorder, diabetes, or “female hysteria.” However, one physician, Dr. John G. Sotos, has a new theory, The New York Times reports.

Sotos recently published a paper in Perspectives in Biology and Medicines suggesting that Mary Todd Lincoln may have had pernicious anemia—a disease caused by a vitamin B12 deficiency.

Sotos is a cardiologist and technology executive at Intel who, while working as a medical consultant for the TV show House, was tasked with brainstorming diagnoses for mysterious health conditions. This experience paid off: Sotos was researching a self-published book about President Abraham Lincoln’s health, The Physical Lincoln, when he discovered an 1852 letter Mary Todd Lincoln wrote that mentions her aching mouth.

Since vitamin B deficiencies can cause a sore tongue, Sotos examined Mary Todd Lincoln’s other documented symptoms. He concluded that, combined with her mental problems, her long list of physical ailments—pallor, fevers, weakness, fatigue, headaches, a fast heartbeat, swelling in her hands and face, mysterious weight loss, and eye problems—fit the bill for pernicious anemia.

Mary Todd Lincoln also had physical traits that are common among people with this disease, including a stocky body, a wide face and jaw, and wide-set blue eyes, Sotos writes. Further cementing the doctor's posthumous hunches, the former First Lady's parents hailed from a region of Scotland where researchers once found pernicious anemia to be common in the 1960s.

Pernicious anemia’s onset is gradual and stems from the body’s inability to absorb enough vitamin B12. Since the body needs it to make DNA, vitamin B12 deficiencies can affect its ability to produce red blood cells, and harm the brain and nervous system. In 1948, scientists developed a monthly shot so people with B12 deficiencies could stay healthy; today, the condition can be spotted with blood tests. But back in Mary Todd Lincoln’s day, there were no such shots or screenings, and people were left to suffer and die.

Sotos fully explains his diagnosis in his new self-published book, The Mary Lincoln Mind-Body Sourcebook. He tells CNN that "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."

Still, other medical experts say that Sotos’s diagnosis is highly speculative, even though it’s believable. They also point out that no matter what condition Mary Todd Lincoln had, it was deserving of empathy—and that we should be no less compassionate about a highly stigmatized condition, like a mental illness, than a B12 deficiency.

[h/t The New York Times]

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