When Hearts Swap Personalities: Exploring the Phenomenon of Personality Changes After Heart Transplantation
Can a heart transplant change someone’s personality? It’s a question that has confused both medical professionals and the public alike. When you undergo heart transplantation, there is a possibility that certain traits may come along with the transplanted heart . In this article, we will explore the fascinating topic of whether personality changes can occur after a heart transplant.
In this article, we will explore the following contents:
1. Importance and history of the heart
2. History of heart transplantation
3. Current statistics about cardiac transplantation
4. The hypothesis
5.Counter arguments
6. Conclusion
1. The cardiocentric hypothesis
The history of the heart spans thousands of years, with a rich and varied cultural and scientific heritage. The cardiocentric hypothesis was the historical belief that the heart controls sensation, thought, and body movement. The Egyptians believed that the heart was the center of the soul and the seat of emotions, while the ancient Greeks regarded it as the seat of intelligence and the source of all vitality. Galen, a Greek doctor and philosopher in his book, “On the Usefulness of the Parts of the Body” says:
“The heart is, as it were, the hearthstone and source of the innate heat by which the animal is governed.”
Ibn Sina, a philosopher and physician in the Islamic golden age described the heart as the center of the body’s life force and the most vital organ in the body in his book, “The Canon of Medicine”. He believed that the heart was responsible for maintaining the balance of the body’s vital fluids and quotes, “The physician must know and believe that it is not his concern whether the heart is or is not the source of sensation, and whether or not the brain is the source of voluntary movement and the liver that of nutritive faculty. The fact is that the heart in relation to all other organs, is the source of psychic actions”.
2. History of heart transplantation
By the 19th century, heart disease had become one of the leading causes of death in the world, prompting researchers to focus their efforts on the study of heart disease and its treatment.
The history of heart transplantation marks a significant milestone in medical science, revolutionizing the treatment of end-stage heart failure.
American medical researcher Simon Flexner was one of the first people to mention the possibility of heart transplantation. In 1907, he wrote the paper “Tendencies in Pathology” in which he said that it would be possible one day by surgery to replace diseased human organs – including arteries, stomach, kidneys, and heart.
The first successful heart transplant took place on December 3, 1967, performed by Dr. Christiaan Barnard in Cape Town, South Africa. Three days after that surgery, Dr. Adrian Kantrowitz performed the first pediatric heart transplant in New York.
3. Statistics
More than 3,000 heart transplants are performed annually in the world.
Over the past 5 years, the number of donor hearts has increased; however, the actual donor to transplant ratio has declined. In other words, although the number of transplanted hearts continued to increase, the percentage of transplanted hearts has decreased over time.
This is due to the higher availability of organs from donors who have died from drug overdose or have hepatitis C. Recent donors also have more co-morbid illnesses (hypertension, diabetes mellitus, obesity, etc).
According to the United Network for Organ Sharing (UNOS) from 10/1/1987 until 1/31/1997, 18,762 people had heart transplants in the U.S. During the same period, 560 people had two heart transplants, and seven had three heart transplants. No one had a fourth heart transplant during that time.
Paul Pearsall, Ph.D. at University of Hawaii, collected a sum of 23 heart transplant cases reporting trait changes. However, the number of patients who had heart transplantation and didn’t report personality changes far exceeded Dr Paul’s cases. “Because the cases were collected sporadically in clinical situations, it is not possible to calculate the percent of patients who reported personality changes”. Says Dr Paul. The total number of cases is not mentioned.
4. The hypothesis
Some experts argue that after a successful heart transplantation, the recipient receives some traits of the donor. They concluded that memories and feelings are stored in the (possibly neurons) heart. Some even say that the human mind is in his heart, not in the brain (CNS). We will explore both sides of the argument.
Most research hypothesizes that cellular memory contributes to the personality changes following heart transplantation surgery in which the recipient assumes the personality traits of the donor. Memories from the donor’s life are hypothesized to be stored in the cells of the donated heart and are then “remembered” by the recipient following transplant surgery. The most important types of cellular memory are epigenetic memory and neuro-cardiac memory.
Although memory is customarily attributed to changes in the nervous system, other types of memory exist as well. For example, immunological memory involves the immune system’s ability to remember pathogens, tumour cells, and to distinguish self from non-self-tissues. Immunological memory is not stored in synapses or neurons but instead resides in the cells of the immune system. Cellular memory has previously been suggested to explain the transfer of personal memories from donor to recipient following heart transplantation.
Some notes on these cases:
- These cases were very unusual in that the change was pretty obvious and was observed and verified by family members of the recipient.
- The recipient knows nothing about the donor’s personality. The recipient does not have any information on the cause of death, age, or personality of the donor.
So far, 4 main categories of changes in patients with a transplanted heart have been reported:
1. Changes in preferences: musical, sexual, and aversions in art and colors were reported. Changes in food preferences are reported by numerous individuals and include differences in both the types of food preferred as well as the amount of food eaten.
For example, a 29-year-old woman who received the heart of a 19-year-old donor who was a vegetarian related: “I hate meat now. I can’t stand it. I was McDonald’s biggest money maker, and now meat makes me throw up. Actually, when I even smell it, my heart starts to race“.
2. Changes in emotion: Two types of emotional changes are reported following heart transplantation.
First, some recipients experience specific emotions that they identify as originating from the donor.
Second, changes in temperament after receiving a new heart.
For example, one recipient stated, “The new heart has changed me……..the person whose heart I got was a calm person, not hectic, and his feelings have been passed on to me now”.
3. Identity change: Some individuals have dreams or memories of their donor’s identity. For example, a 48-year-old female recipient wrote about a dream she had 5 months after her transplant:
“It’s a warm summer day. I’m standing in an open, outside place, a grassy field. With me is a young man who is tall, thin, and wiry, with sandy coloured hair. His name is Tim, and I think his last name may be Leighton, but I’m not sure. I think of him as Tim.” Later, she learned her donor was an 18-year-old man named Tim Lamirande.
4. Memories from their donors: some recipients describe “memories” that do not coincide with events from their own lives. These memories, which may occur during waking consciousness or sleep, include sensory experiences related to their donor. For example:
A 56-year-old college professor received the heart of a 34-year-old police officer who was killed after being shot in the face while attempting to arrest a drug trafficker. The recipient described: “A few weeks after I got my heart, I began to have dreams. I would see a flash of light right in my face and my face gets real, real hot. It actually burns”.
It is generally assumed that learning involves primarily the nervous system and, secondarily, the immune system. But if those systems were the sole repository of memory, then patients receiving peripheral organ transplants should not experience personality changes parallel to those of donors they have never met.
Epigenetic memory:
Epigenetics is the study of factors that influence transcription of the genome without altering the DNA sequence. Epigenetic modifications act like a switch that can turn genes on or off, leading to changes in gene expression that can either enhance or suppress the production of a gene’s product. Persisting epigenetic changes create an epigenetic code that determines whether a specific gene is transcribed and encodes information that can be stored and retrieved over time. The entirety of an individual’s epigenetic changes at any given point in time is known as the epigenome.
In summary, the epigenetic code refers to the specific patterns of chemical modifications (methylation, histone modification) involved in gene regulation, while the epigenome encompasses the entirety of these modifications in each cell or tissue.
Information saved in the epigenome provides a historical record of interactions between an individual and the environment. Stored via chemical and structural alterations of chromatin or short strands of RNA, this information persists as a type of cellular memory known as epigenetic memory. In some cases, epigenetic memory can be passed down to an individual’s progeny through a process known as transgenerational epigenetic inheritance or epigenetic inheritance. The epigenome provides a mechanism for encoding, storing, and retrieving interactions between the environment and an individual’s genome, like the way the genome provides a historical record of the interactions between a species and its environment.
That being said, if information about the environment, physiology, and pathology of the heart are stored in the epigenome and could be retrieved later just like memories in the brain, this may contribute to the personality change of the recipients.
Cardiac neurological memory:
The heart has two distinct networks of nerves:
1. One consisting of nerve cells within the heart.
2. The other is made up of nerves originating outside the heart.
Both networks have the potential to encode, store, and retrieve memories. However, only the nerves within the human heart are transplanted with the heart. These nerves are known as the “intracardiac nervous system.”
According to the latest research in 2018, the human intracardiac nervous system (ICNS) is made up of 700 – 1500 intracardiac ganglia (ICG), each composed of 200 – 1000 neurons. Groups of ICG combine with interconnecting nerves to form ganglionated plexi (GP), which are in specific regions of the heart. Each group of ICG contains sensory, efferent, and interconnecting neurons that control multiple cardiac functions, but the structural organization of ICG and intracardiac neurons varies considerably from heart to heart and is greatly affected by age. Based upon similarities with the cerebral brain, this complex system of neurons has been termed the “heart brain”.
Neurons in the heart communicate with one another via the release of neurotransmitters, many of which are also found in the brain. The most common one is norepinephrine (NE). Others include serotonin (5-HT), histamine (H), L-DOPA (levodopa), dopamine (DA), acetylcholine (Ach), vasoactive intestinal peptide (VIP), and nitric oxide (NO).
The intracardiac nervous system has been found to remodel itself after cardiac transplantation, a process known as neuroplasticity. Neuroplasticity is one of the fundamental characteristics of the cerebral brain that is believed to be involved in the formation, storage, and retrieval of memories. Thus, memories may be stored within the intracardiac nervous system and are transferred to the recipient at the time of transplantation.
5. Counter arguments
One hypotheses to explain the sudden personality change of receipts, argues that personality changes after heart transplantation could be due to endocrine dysfunction. Researchers have found that heart transplant recipients who undergo endocrine testing sometimes show variations in hormone levels. These changes in hormone levels can influence an individual’s mood, behavior, and cognition, leading to alteration in their personality.
Explanations that have been offered for personality changes observed following transplants include the effects of the immunosuppressant drugs, psychosocial stress, and pre-existing psychopathology of the recipients.
The first thing to consider is that heart transplantation surgery is a near-death experience. With that being said, it is not a surprise for patients to change after a near-death surgery. If the recipient had any pre-conception about personality change after heart transplantation, it makes the case even more biased.
Jeff Punch, a surgery professor says that there are several possible logical explanations for why people might assume characteristics of their donors: Side effects of transplant medications may make people feel weird and different from before the transplant. Transplant medications are corticosteroids (prednisolone or prednisone, dexamethasone) and drugs for autoimmune diseases.
“For example, prednisone makes people hungry: The recipient of an organ transplant develops a love of pastry and finds out the person that donated their organ loved pastry as well. They think there is a connection, but really it is just the prednisone making their body crave sweets.” States professor Jeff.
Another interesting argument is that made with total artificial heart (TAH). If memories and feelings reside in the heart, and if the human mind is in the heart, as some say, then how can they explain the case of people with total artificial heart? Patients with TAH have reported episodes of anxiety and depression, however this is due to the stress of TAH being a temporary solution for patients of end-stage heart failure until a donor heart is available. A person can live with an artificial heart for several months or even years while waiting for a transplant. Once patients recover from surgery, they feel stronger and healthier than they did before receiving the total artificial heart.
6. Conclusion
This topic remains largely uninvestigated and many questions remain to be answered. How common are personality changes following heart transplantation? Are these changes temporary or permanent? Is the donor dead if their heart continues to sense and respond to the environment? Why are these personality changes not observed in people with artificial hearts?
Many questions regarding cellular memory remain to be answered as well. For example, what types of information can be stored in the epigenome and how resilient is this storage? What about identity? Can an individual’s name be stored in their cells?
In addition to heart recipients, kidney, liver, and other organ recipients also indicated changes in sense of smell, food preference, and emotional factors. However, these changes were usually transitory and could be associated with medications and other factors of transplantation. The findings for heart transplants appear more robust and more strongly associated with the donor’s history.
In conclusion, the scientific evidence on the topic is insufficient to make any conclusive statements. Future research is necessary to investigate the recipient-donor coincidence phenomenon systematically.
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