Mental symptoms of Alzheimer’s disease –

Sweden has just over 100,000 people diagnosed with Alzheimer’s disease. Cognitive symptoms combined with elevated levels of beta-amyloid proteins and phosphorylated tau form the basis for the diagnosis. But over the past decade, the theory that changes in mood and behavior can be very early signs of disease with symptoms has not received as much scientific attention as cognitive symptoms.

Now, researchers from Lund University, Skene University Hospital and the Cognitive Medicine Unit in Angelholm have jointly investigated the complex links between mental symptoms, Alzheimer’s proteins, and cognitive symptoms. This was done within the framework of the world-renowned BioFINDER study, led by Professor Oscar Hanson.

The study examined 356 people over the age of 65 who had no cognitive problems at the start of the study. In addition to analyzing beta-amyloid and phosphorylated tau in the spinal fluid, participants’ anxiety and apathy levels as well as cognitive function were also examined every two years. Study participants were followed for eight years.

Mental symptoms – as a result of changes in the brain

When analyzing the data, the researchers found a link between elevated levels of beta-amyloid at the start of the study and the future development of anxiety and apathy.

Moritz Johansson, a doctoral student at Lund University, physician in the Cognitive Medicine Unit at Angelholm Hospital and lead author of the study explains:

Alzheimer’s disease affects large parts of the brain, including the areas that control our emotional lives. Our study shows that mental symptoms, just like cognitive disorders, are the result of changes in the brain as a result of amyloid-beta storage.

The researchers also showed that amyloid beta drives the development of apathy primarily through direct influences, and that apathy is caused only to a limited extent by cognitive impairment. Regarding anxiety, no association with cognitive changes was observed.

The results therefore suggest that these early changes in emotional life and behavior in Alzheimer’s disease will primarily constitute psychological reactions to the diminished cognitive ability. Instead, the findings suggest that apathy and at least anxiety arise from the pathological accumulation of certain proteins associated with Alzheimer’s disease, explains Oscar Hanson, professor of neuroscience at Lund University and chief medical officer at Skene University Hospital.

Psychological symptoms as alternative outcome measures

The results also mean that the mental symptoms of Alzheimer’s disease can be used as alternative outcome measures in treatment studies. Ultimately, this could lead to a more efficient study design, he continues.

A previous study in BioFINDER suggests that the presence of anxiety or apathy in older adults without dementia may indicate an increased risk of future cognitive decline.

In the next step, studies are needed to clarify how these symptoms may contribute to a well-established clinical diagnosis during the early stages of the disease, and then in some cases perhaps even before cognition is affected.

Scientific material:

The development of apathy, anxiety, and depression in non-cognitively impaired older adults: implications for Alzheimer’s pathology and cognitive decline..

Text: Martina Svensson

The article was previously published as news from Lund University