Medical Bulletin 28/ March/ 2025 - Video

An adult brain affected by attention deficit disorder with or without hyperactivity (ADHD) presents modifications similar to those observed in individuals suffering from dementia. These are the findings of a study conducted by the Geneva University Hospitals (HUG) and the University of Geneva (UNIGE) which shows that, compared with healthy individuals, patients with an ADHD diagnosis have more iron in certain regions of their brain along with higher levels of neurofilaments in their blood.

These markers have been consistently reported to be characteristic of old age-related dementias such as Alzheimer's disease and can be measured in its early stages. The study confirms that ADHD may be linked to an increased risk of developing dementia later in life and it provides first evidence for a neurological mechanism possibly involved. This significant step forward is described in the journal Psychiatry and Clinical Neurosciences.

The research team used an advanced brain imaging method, known as quantitative susceptibility mapping (QSM) through magnetic resonance imaging (MRI) to examine iron content in the brain of 32 adults between 25 – 45 years of age affected by ADHD and 29 healthy individuals in the same age bracket. Neurofilament light chain protein (NfL) levels in the blood of the participants were measured in parallel. The results of the study reveal notable differences in iron distribution in several regions of the brain of the individuals affected by ADHD. Furthermore, a significant association was established between iron levels in the precentral cortex and NfL levels in the blood.

Iron plays an essential role in normal brain functioning, but its excessive accumulation may cause neuronal damage and lead to neurodegenerative diseases such as Alzheimer's disease.

In parallel, the NfL is an indicator of neuronal damage in the brain, more specifically of neuronal axons which are essential for nerve transmission. High blood levels of NfL reflect axon damage in the brain. Consequently, an increased brain iron and NfL levels may indicate an underlying neurodegenerative pathology and an increased risk of neurodegenerative dementia at old age.

These results confirm that a link exists between ADHD and an increased risk of dementia at old age and identify first neurological mechanism.

Ref: Berberat J, Kagerer S M et al. Brain iron load and neuroaxonal vulnerability in adult attention-deficit hyperactivity disorder. Psychiatry and Clinical Neurosciences; 27th Feb, 2025. https://doi.org/10.1111/pcn.13806

Compared with those who spent most of their time in a single room, people with heart failure with preserved ejection fraction (HFpEF) who were able to travel outside of their home without assistance were significantly less likely to be hospitalized or die within a year, according to a study being presented at the American College of Cardiology’s Annual Scientific Session.

The findings underscore the value of supporting holistic care and encouraging people with heart failure to maintain an active lifestyle and engage with others in their community to the extent possible, researchers said.

The study used a metric known as life-space mobility to quantify the degree to which patients moved around in their communities over the course of one month. Life-space mobility has been shown to be a reliable marker of risk of adverse outcomes in people with a variety of chronic diseases, including chronic obstructive pulmonary disease, chronic kidney disease and peripheral artery disease, but the new study is the first to assess it in the context of HFpEF.

To assess whether life-space mobility could offer insights relevant to HFpEF care, researchers administered questionnaires to 175 consecutive patients treated for HFpEF at Weill Cornell Medical Center between 2019-2023. They then evaluated the relationship between patients’ life-space mobility scores and their likelihood of dying or being hospitalized within one year, the study’s composite primary endpoint.

Analysis revealed that those who scored in the lowest tertile for life-space mobility were 2.4 times more likely to die or be hospitalized within one year compared with those in the highest tertile. The researchers found that patients who were less likely to leave their homes than those who were more independent were significantly more likely to suffer these outcomes even after accounting for race and MAGGIC score, a clinical calculator that has been demonstrated to predict adverse outcomes among patients with HFpEF on other validated risk assessment tools.

Multiple factors could influence whether a patient is able to move beyond their room or home, and researchers were not able to directly account for factors such as medication adherence that may play a role.

Ref: Association of Life-Space Mobility and All-Cause Hospitalization and Mortality Among Older Adults with HFpEF. American College of Cardiology's Annual Scientific Session

A new study published in The Journal of Immunology found that a high-salt diet (HSD) induces depression-like symptoms in mice by driving the production of a protein called IL-17A. This protein has previously been identified as a contributor to depression in human clinical studies.

The researchers also identified a type of immune cell called gamma-delta T cells as an important source of IL-17A in HSD-fed mice, accounting for ~40% of IL-17A-producing cells.

High-salt intake is ubiquitous in the Western diet, with fast foods often containing 100 times more salt than a home-cooked meal. HSD is already an important public health concern as it is linked to cardiovascular, autoimmune, and neurodivergent diseases. Furthermore, major depression disorder is also a significant public health concern with a lifetime prevalence of 15-18%.

In this study, mice were fed a normal diet or HSD for 5 weeks, a common timeframe used to study excessive dietary salt intake. After five weeks, the mice fed the HSD showed less interest in exploring and more inactivity in various scenarios compared to mice fed a normal diet, suggesting depression-like symptoms in mice

Given the already established role of IL-17A in the development of depression, the research team also investigated whether HSD induced IL-17A production in mice. HSD increased IL-17A levels in the spleen, blood, and brain, correlating with anxiety- and depression-like behaviors. However, when mice that could not produce IL-17A were fed an HSD, depression-like symptoms were not observed, confirming the role of IL-17A in developing depression-like symptoms.

These findings corroborate epidemiological evidence that HSD correlates strongly with more severe depression and studies in people demonstrating that low sodium intake is closely associated with good mood.

Ref: Lu D, Chen W et al. High-salt diet drives depression-like behavior in mice by inducing IL-17A production, The Journal of Immunology, 2025;, vkaf019, https://doi.org/10.1093/jimmun/vkaf019