There has long been a debate about whether Alzheimer’s disease could ever pass from one person to another. Today, experts say the chance of such a transmission is extremely small. This conclusion comes from a careful review of historical medical data and recent scientific discussions.
A landmark assessment in the medical literature connected to a historical practice raises questions about transmission. In the late 20th century, medical teams used human growth hormone sourced from brain tissue from deceased donors to treat certain conditions. Those donor-derived hormones were administered between 1959 and 1985. In the years that followed, about 200 patients treated with these hormones developed Creutzfeldt-Jakob disease, a prion-related brain disorder known for causing rapidly progressive dementia. A subsequent study noted a surprising parallel: Alzheimer’s disease could be shown to share a transmission pattern with prion diseases under very specific circumstances. This finding prompted extensive discussion within the scientific community about the biological mechanisms that can spread protein defects in the brain.
Alzheimer’s disease is characterized by two abnormal proteins that accumulate abnormally in brain tissue: amyloid and tau. The current body of evidence indicates that these proteins can spread through brain networks in a manner reminiscent of prion diseases. The recent research contributes to that growing understanding and highlights the potential for disease-related proteins to propagate in ways once thought unlikely.
Reports describe potential instances of Alzheimer’s disease diagnosed in adults aged 38 to 55, raising important questions about how and when transmission could occur under historical medical practices. While these cases exist in the broader context of historical hormone treatments, they are exceedingly rare relative to the global population who received donor-derived therapies. The research described as foundational in nature shows that Alzheimer’s disease can appear to be transmitted in a manner similar to prion diseases under certain conditions, but this does not imply everyday risk in clinical or caregiving settings. In public discussions about this topic, it is important to distinguish between specific, exceptional scenarios and the standard understanding of Alzheimer’s as a condition that develops over a lifetime rather than through casual contact or routine medical care.
Earlier medical opinions suggested reversible dementia in some situations, but current evidence and consensus emphasize Alzheimer’s as a progressive neurodegenerative condition driven by complex biological processes. The evolving conversation within the scientific community continues to refine how researchers assess transmission pathways, the role of protein misfolding, and what safeguards might minimize any theoretical risk in medical procedures. The overall takeaway remains that the possibility of transmission in ordinary circumstances is highly limited and not representative of everyday experiences for patients, families, or caregivers.