Study Links ADHD to Higher Dementia Risk Through Neurological Mechanisms - 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