In my nearly 40-year career as a psychiatrist, I’ve received some unusual calls, but the one from Mary* was unique.
“Dr. Riester, I don’t need to see you as a patient. I just want you to tell me if I’m crazy. You see, I have memories of things that have never happened before. .”myself. “
That piqued my interest so we agreed to meet for an appointment.
Mary was a cheerful, intelligent woman in her mid-40s who showed no signs of mental illness. In fact, she seemed very reasonable and easy to engage in conversation. She began to explain the reason for her call. Mary had been experiencing recurring intrusive memories that last year she had been hit by a car. In these “memories” she is a pedestrian and she not only witnesses herself being hit by a car, but also the impact of the car hitting her torso and sending her flying into the air. I felt it. The problem was that Mary had never been hit by a car. Asked about her trauma, Mary said she underwent heart transplant surgery just before these new memories began. Her transplant surgery went well, but she wondered, “Does my new heart have anything to do with these new memories?”
Mary then revealed that she had recently learned the identity of her donor’s family. They live in Seattle and she was scheduled to visit them next week. I reassured Mary that she wasn’t crazy, and she ended her appointment by asking if we could meet again when she returned from her trip. she agreed.
When Mary returned, she explained what she had learned on her trip. Her donor was a prepubescent boy who was playing tag with her friends when she ran between two houses and into an alley where she could not see the car approaching. He was struck by a car in the same place that Mary experienced the sensation of being hit. The boy was declared brain dead, but his heart was intact, so his parents donated his heart. Mary’s reaction to learning this information was one of relief and closure. She now knows that she is not “crazy.” But I wondered: Will organ transplants cause personality changes?
Related research
One of the earliest patient testimonies describing changes in personality after an organ transplant is found in the writings of Claire Sylvia. change of heartpublished in 1997, and it wasn’t until the 1990s that researchers began investigating this phenomenon.
in one early studies In this field, neuropsychologist Dr. Paul Pearsall investigated personality changes in 10 heart transplant recipients to see if they matched the donor’s personality. In each case, he interviewed the heart transplant recipient, the donor’s family, and the recipient’s family. He found 2 to 5 similarities in each case between the changes in the recipient’s personality and the donor’s personality after the transplant. These include changes in tastes in food, music, art, sex, recreation, and career.
He also found specific instances in which recipients were able to identify the donor or had sensory experiences associated with the donor.in another studyIt is explained in detail in his 1998 book. code of the heartDr. Pearsall explained that recipients of kidneys, livers and other organs also experience post-transplant changes, including their sense of smell, food preferences and emotions, but these changes are usually temporary and heart transplant recipes. reported that the changes were not as robust as those observed in patients.
Recently, we have conducted research A study on this topic at the University of Colorado School of Medicine found that 89% of organ recipients (of any organ) reported personality changes after transplant surgery.
These findings raise the question: What causes these personality changes? A number of hypotheses have been proposed, including the effects of immunosuppressive drugs, the trauma of undergoing transplant surgery, and secret acquisition of information about the donor from outside sources. Pearsall suggested another possibility and hypothesized that cellular memory may be to blame.
Where are the memories stored?
1894, Spanish neuroscientist Santiago Ramon y Cajal was suggested Memories are stored in the brain. He believed that this memory occurred by rebuilding synapses, the connections between neurons. More than half a century has passed since then, the study Neurosurgeon Wilder Penfield, MD, found evidence that: back this up. The theory that memories are stored in synapses in the brain continues to this day.
However, memories stored in the brain alone are unlikely to explain the personality changes observed after organ transplants. Could different types of memory explain these changes?
Several types of non-neurological cellular memory exist. For example, the immune system remembers exposure to infectious agents and responds more quickly if re-exposure occurs.This is known as immunological memory.
Another form of cellular memory involves DNA. The DNA in our cells is huge amount of information. Almost every cell in the body is known to secrete DNA-containing packages known as exosomes, which circulate throughout the body and deliver their contents to other cells, where they become incorporated into the DNA of recipient cells. . Is it possible that a donor organ secretes exosomes to deliver DNA to the organ recipient’s cells, thereby transferring DNA-encoded memories about the donor?
epigenetic memory Another type of cellular memory. Epigenetics is the study of factors that turn genes on or off without changing the DNA sequence. Different types of epigenetic changes occur in human cells, and these changes create an epigenetic code that is stored and retrieved over time.
The totality of an individual’s epigenetic changes at any given time is epigenome. The epigenome can be seen as a record of interactions between the individual and the environment and is known as a type of cellular memory. epigenetic memory. Just as DNA memory is transferred between cells via exosomes, epigenetic changes associated with DNA can also be exchanged between cells, allowing information to be transferred between donor and recipient cells. The possibility of a means of communication has been suggested.
RNA memory It might even be a game. UCLA researchers used sea slugs Aplysia to demonstrate memory transfer between individuals. These animals were given repeated electrical shocks to their tails, which fixed the memory of the shocks. They then took the RNA from the trained animal and injected it into a naive animal, which responded as if it had been trained to respond to an electric shock. This demonstrated that memory can be transferred via RNA and raised the possibility that organ donor memories are transferred to recipients via RNA-containing exosomes.
Another potential way to transfer memories involves proteins. Over 20 years ago, Sandra Peña de Ortiz and Yuri Arshavsky made a hypothesis A new protein could encode long-term memory. Exosomes are known to transfer proteins between cells, suggesting that memories stored in such proteins may be exchanged between donor organs and recipients.
influence
So far, the jury is out on these theories, and more research is needed.But if you have memory and personality traits can The possibility of organ replacement through transplantation suggests multiple potential effects of organ transplant surgery. Organ transplants not only affect the recipient’s identity and personality, but can also affect relationships and the outcome of the surgery. For example, my patient Mary wanted to stop taking her immunosuppressants. Because she believed that her new heart had been “integrated,” she believed that it would not reject her heart even if she stopped taking the medication. Such decisions can have dire consequences, including rejection of donated organs and death.
Our goal
Further research exploring changes in personality after organ transplantation may tell us: kinds In addition to understanding possible personality changes, you will also gain a better understanding of different aspects of personality and the different processes involved in memory storage and retrieval. Although the anecdote does not prove that personality changes occur as a result of organ transplantation, it does suggest the possibility of such changes and provides a starting point for further exploration of this fascinating area of medicine. We provide.
*Patient’s name has been changed
Mitch Riester, MD, is a clinical assistant professor in the Department of Psychiatry at the University of Colorado School of Medicine.
