Behavioural changes such as irritability, sleep changes and depression are common characteristics in the early stages of familial Alzheimer's disease, according to research published in Brain.

Researchers, including Professor Martin Rossor, UCL Institute of Neurology, sought to characterise early behavioural features in carriers of autosomal dominant Alzheimer’s disease mutations. 

The results underpin our understanding that it is possible to map the progression of familial Alzheimer’s disease from the pre-manifest phase to the development of symptoms. In this study, psychiatric features appear to occur in an early symptomatic phase rather than being life-long traits. Understanding when and why features such as depression occur in the disease will be important for helping patients, especially since features of depression and anxiety are often not recognised or actively enquired about. In addition, it remains difficult to understand to what extent these features are a response to functional impairments, or if the disease process is guiding psychiatric presentations Professor Rossor, Director of the NIHR Queen's Square Dementia Biomedical Research Unit

In the study 155 people with or at-risk for autosomal dominant Alzheimer’s disease (97 asymptomatic, 25 mildly symptomatic and 33 overtly affected carriers) were evaluated with formal questionnaires: the neuropsychiatric inventory-questionnaire, the 15-item geriatric depression scale and the clinical dementia rating scale. The participants were compared to 106 non-carriers. Depression, apathy, disinhibition, irritability, sleep changes and agitation were more common and the degree of self-rated depression more severe in mildly symptomatic mutation carriers compared to non-carriers.

Scientists have already determined patients who carry the gene mutation will develop familial Alzheimer’s disease. As a result they are able to obtain a detailed understanding of the natural history of the disease using molecular markers in cerebrospinal fluid, imaging and cognitive changes. Previous smaller studies of patients with familial Alzheimer’s disease and population studies has suggested psychiatric symptoms, particularly depression, are found with early disease and may precede the development of cognitive impairment.

The study emerged from the Dominantly Inherited Alzheimer’s disease (DIAN) network, an international collaboration of leading scientists set up to characterise early clinical and biomarker changes occurring in patients with Autosomal Dominant Alzheimer’s disease.

Further information:

Ringman et al. (2015)  Early behavioural changes in familial Alzheimer’s disease in the Dominantly Inherited Alzheimer Network Brain 138, 1036-1045. http://dx.doi.org/10.1093/brain/awv004