U.S. and Danish researchers have found an unexpected link between Lyme disease and mental health. The study revealed that patients hospitalized with Lyme disease had a 28% higher rate of mental disorders. They also had twice the likelihood of attempting suicide after being infected compared to people without Lyme disease.
Columbia University and the Copenhagen Research Centre for Mental Health collaborated on the study. In fact, it marked the first large, population-based study of its kind to investigate the link between Lyme disease and mental health. The research was published in the July 28, 2021, online edition of the American Journal of Psychiatry.
What is Lyme disease?
Lyme disease is an infection caused by a spiral-shaped bacteria called Borrelia burgdorferi. It’s normally transmitted to humans by a tick bite. The first sign of Lyme disease is usually around or oval-shaped red rash that resembles a bullseye. The disease’s name comes from the first place it was discovered: Lyme, Connecticut.
When is tick season?
Tick season occurs from April to October, but humans can contract Lyme disease year-round. Aside from a rash, other symptoms of Lyme disease tend to occur after a few days or weeks. They include flu-like symptoms such as the following:
- Stiff neck
- Muscle and/or joint pain
- Low-grade fever and chills
- Decreased appetite
- Swollen glands
Know the importance of seeking treatment
If left untreated for weeks or months, Lyme disease can also cause neurological and heart problems. It also leads to a 60% chance of developing Lyme arthritis or inflammation of joints due to Lyme disease.
“It is time to move beyond thinking of Lyme disease as a simple illness that only causes a rash,” said Brian Fallon, MD, MPH, a psychiatrist with the New York State Psychiatric Institute and Columbia University who is the lead author of the paper. “In addition to the risk of severe cardiac, rheumatologic, and neurologic problems, Lyme disease can cause severe mental health problems as well.”
Dr. Fallon is one of the leading researchers of the association between Lyme disease and psychiatric disorders. He’s also the director of the Lyme and Tick-borne Diseases Research Center at Columbia. Other investigators on the study included Michael Benros MD, Ph.D., principal investigator; Trine Madsen, Ph.D., co-first author; and Annette Erlangsen, Ph.D., all psychiatric epidemiologists at the Research Centre for Mental Health.
Lyme disease appears to link to higher suicide rates.
For the study, researchers analyzed the medical records of almost 7 million people in Denmark over a 22-year period. They compared the mental health data of individuals hospitalized with Lyme disease to people who had never had a Lyme diagnosis. Researchers excluded patients with a history of mental disorders or suicidality before the Lyme disease diagnosis.
The study found that patients with Lyme disease had a higher risk of mental disorders and suicide attempts. Specifically, they had a 42% higher rate of affective disorders such as depression and bipolar disorder. Perhaps most disturbing of all, Lyme disease patients had a 75% higher death rate by suicide than those without the diagnosis.
Even worse, being diagnosed with Lyme disease multiple times heightened the rate of mental disorders, affective disorders, and suicidal thoughts.
Nearly 500,000 people contract Lyme disease annually in the U.S.
Each year, almost 500,000 people in the U.S. get diagnosed with and treated for Lyme disease. Also called Lyme borreliosis, it transfers to humans through the bite of a deer tick infected with the bacteria. Most American cases come from the northeastern, mid-Atlantic, and north-central states. However, according to data from the CDC, nearly every state reported cases of Lyme disease in 2019.
To treat Lyme disease, doctors normally prescribe a two- to a four-week round of oral antibiotics. However, 10-20% of patients report symptoms such as pain, cognitive impairments, or fatigue months or even years after treatment. Several studies have determined a connection between Lyme disease and mental health problems after antibiotic treatment or untreated patients. People with late-stage Lyme disease may experience the following symptoms in severe cases:
- difficulty concentrating
- memory and sleep problems
- painful nerve disorders
However, Dr. Michael Benros says that most people don’t experience severe mental health issues after contracting Lyme disease. The study found that only 7% of almost 13,000 individuals diagnosed with Lyme disease complained of mental problems. They followed up with hospital clinicians who determined the link between Lyme disease and mental health issues. Most people fully recover from Lyme disease after treatment.
We must not ignore the link between Lyme disease and mental health.
Researchers say these unexpected findings warrant more attention from the public regarding the risks of Lyme disease and mental health problems. Unfortunately, it’s likely a more widespread issue than the data portrays. The Danish medical registry only includes psychiatric diagnoses made in hospitals. With clinicians’ diagnoses, the number of people suffering new onset mental problems following Lyme infections is probably much higher.