Loss of pleasure identified as feature of early-onset dementia

Sydney-led research has uncovered profound anhedonia as a key feature in early-onset dementia, with grey-matter deterioration in the so-called pleasure system of the brain, suggesting a possible treatment target.

People with early-onset dementia are often mistaken for having depression and now Australian research has discovered the cause: a profound loss of ability to experience pleasure – for example a delicious meal or beautiful sunset – related to degeneration of ‘hedonic hotspots’ in the brain where pleasure mechanisms are concentrated.

University of Sydney-led research has revealed marked degeneration, or atrophy, in frontal and striatal areas of the brain related to diminished reward-seeking, in patients with frontotemporal dementia (FTD).

The researchers believe it is the first study to demonstrate profound anhedonia – the clinical definition for a loss of ability to experience pleasure – in people with FTD. Anhedonia is also common in people with depression, bipolar disorder and obsessive-compulsive disorder and can be particularly disabling for the individual.

In the study, patients with FTD – which generally affects people aged 40-65 – displayed a dramatic decline from pre-disease onset, in contrast to patients with Alzheimer’s disease, who were not found to show clinically significant anhedonia.

The results point to the importance of considering anhedonia as a primary presenting feature of FTD, where researchers found neural drivers in areas that are distinct from apathy or depression.

The findings were published today in the leading neuroscience journal, Brain.

A total of 172 participants were recruited, including 87 FTD, 34 Alzheimer’s disease participants. Using brain imaging, researchers found that the loss of pleasure related to degeneration in a discrete set of regions in the so-called pleasure system of the brain.