Does a Transplant Change Not Only the Heart but Also "Me"? ─ The Science Behind "Personality Changes"

The Question is Old, Yet New—"Does Transplantation Change 'Me'?"

On August 17, an article published by UOL's health media VivaBem presented a translation of an essay that links the topic of "personality change" often associated with heart transplants to the latest science and physiology. The original contribution is from the UK media The Conversation, authored by anatomist Adam Taylor. There are two main points. First, the change may not be limited to the heart. Second, the background can be explained not only psychologically but also through biological mechanisms.UOLtheconversation.com

How to "Read" the Number 89%

A small-scale study (n=47) published in an MDPI journal in 2024 reported that 89.3% of organ transplant recipients, including heart transplants, self-reported "some kind of personality change." The general trend was similar between heart and other organs, with statistically significant differences limited to "changes in physical attributes." However, the recruitment method focused on Facebook and support groups, which the authors themselves emphasized as a "selection bias" that makes it easier for those who felt changes to participate. Therefore, it does not serve as evidence to definitively state "transplants always change personality," but rather as an indication that "not a few people feel changes."MDPI

From Heart to Brain—The Circuit Diagram of Hormones and Nerves

From a physiological perspective, the heart is more than just a circulatory pump. The atria and ventricles secrete peptide hormones such as ANP/BNP, affecting fluid balance, electrolytes, and sympathetic nervous activity (the so-called "fight or flight response"). It has been reported that these peptides tend to remain elevated after heart transplantation, with data indicating they do not fully normalize. Although nerve connections are initially severed during surgery, there is a possibility of partial reconnection over time. This "heart-brain-endocrine" loop is hypothesized to potentially influence changes in mood and behavioral tendencies.UOLPubMedajconline.org

"Otherness" Within the Body—The Reality of Microchimerism

After transplantation, donor-derived cells and DNA can exist in small quantities within the body for an extended period. This is known as microchimerism, and it has been reported in journals such as NEJM. While its immunological significance (relation to tolerance and rejection) is still under research, it is a fact that the "circulation of another's biological information" can persist. Although it cannot be definitively stated that "memories" are transferred, in the context of psychoneuroimmunology, where immune activity and chronic inflammation can influence mood and personality traits, it becomes an element that cannot be ignored.New England Journal of MedicinePubMed

Psychology and Pharmacology—The Impact of "Experience" and "Treatment"

When discussing changes in personality or mood, psychosocial factors and drug effects cannot be overlooked. The process of undergoing the extreme situation of transplantation increases the risk of depression, anxiety, and PTSD-like symptoms. Additionally, immunosuppressive drugs such as steroids and calcineurin inhibitors (tacrolimus, cyclosporine) can affect mood and thought processes depending on dosage and individual differences. Therefore, the answer to "why change occurs" is not a single path but is realistically understood as an overlap of physiology, immunology, pharmacology, and psychology.PMCFrontierspsychiatry-psychopharmacology.com

Social Media Reaction Map—Surprise, Skepticism, and Voices of Those Involved

• Surprise Group (Romantic): The "89% personality change" figure spread widely on social media and became a topic on international forums. Voices attracted to the intuitive "cellular memory" were prominent.Reddit

• Skeptic Group (Fact Check): In the same threads, there were numerous comments pointing out the sample size and selection bias. The authors of the paper also acknowledged the bias and emphasized the need for prospective research.MDPI

• Around the "Ghost Story": Some tabloids sensationalized headlines like "Inherited the Donor's Memories," which, while generating clicks, exaggerated the scientific implications.The SunNew York Post

• Community of Those Involved: On forums for transplant recipients and their families, real discussions tend to focus more on drug side effects, changes in intimacy, and coping with anxiety rather than "personality changes."Reddit

• Observation of Spread: On platforms like Instagram, the "89%" figure tends to be isolated and reproduced, often omitting context (such as research methods and limitations).Instagram

Three Keys to Media Literacy

1. Read Numbers with "Design" in Mind: n=47, self-reported, recruitment path—these three points act as a brake on interpretation.MDPI

2. View Mechanisms as a "Bundle of Candidates": Hormones, nerve reinnervation, immunity/inflammation, pharmacology, and psychological trauma influence each other. Do not reduce to a single cause.UOLPubMed

3. "Inheritance of Memory" is Unproven: Microchimerism is a fact, but the claim that a person's autobiographical memory transfers from organs remains speculative.New England Journal of Medicine

Implications for Practice—Updating Explanations and Support

The authors of the MDPI paper touched on the reality that transplant candidates may harbor anxieties about "whether their personality will change," suggesting that appropriately addressing this theme in pre-transplant explanations could positively impact rejection and medication adherence. Psychological support, medication adjustments, and family education managed by a team—this is close to the best practice in the field.MDPI

Why This Story Still Captivates People

Organ transplantation intersects medicine and human perception. To what extent is our "sense of self" supported by the body? Science is gradually outlining the contours, but the temptation of sensational stories is also strong. What is needed is an attitude of learning caution without letting go of wonder. The conclusion is undecided. However, careful explanations and psychological support for anxiety can be done right now.

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