Depression in Alzheimer's disease: Biomarkers and treatment

Daniela Enache, Graduate Student at Karolinska Institutet´s Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, is defending her doctoral thesis on ”Depression in Alzheimer’s disease: Biomarkers and treatment” on December 18.

Depression and dementia are among the most common clinical syndromes in older people and are associated with important clinical consequences including reduced quality of life, disability and increased mortality.

What are your most important findings?

We have found that patients with Alzheimer's disease (AD) and depressive symptoms have less pathological cerebrospinal fluid (CSF) biomarkers for amyloid and tau accumulation in the brain. Moreover we found that patients with AD and depressive symptoms have larger medial temporal lobe. Our results are surprising as they are contrary to our hypotheses. We expected that patients with AD and depressive symptoms have more pathological changes in the brain.

In a study using SveDem – Swedish Dementia records – we have found that 25 percentage of patients newly diagnosed with dementia use antidepressant treatment. Furthermore, the use of antidepressant treatment three years prior to an Alzheimer’s disease/dementia diagnosis may decrease mortality risk. Our results are similar with finding from another Finnish register based study which found that 29 percentage of patients with dementia use antidepressant treatment. What is of importance is that use of antidepressant treatment three consecutive years in preclinical stages of Alzheimer’s disease/dementia can reduce mortality rates.

In a forth study, we used CAIDE Dementia Risk Score which is a score that takes into account various risk and protective factors for dementia, and can predict the development of dementia after 20 years in the general population. In a memory clinic cohort of patients without dementia we found that CAIDE Dementia Risk Score is associated with pathological CSF biomarkers for amyloid, tau accumulation and imaging biomarkers of medial temporal lobe atrophy and white matter changes. Additionally, CAIDE Dementia Risk Score has the capacity to predict dementia in memory clinic patients with a short follow-up period. Our results confirmed that there are associations between the score and biomarkers of Alzheimer’s disease, explaining at some extent the underlying mechanisms of the score, but also its capacity to predict dementia.

What possible impact will the results have for patients with depression and AD?

We have confirmed other findings that depressive symptoms and use of antidepressants are common among memory clinic patients. Accordingly, in memory clinics screening for depressive symptoms and a critical review of psychopharmacological treatment is important. Effective multimodal management strategies are needed. Our findings that antidepressants do not increase mortality in patients with early AD, and might even reduce mortality, are re-assuring, and suggest that antidepressants are safe in these patients.

CAIDE Dementia Risk Score can aid in the dementia risk assessment of patients with subjective and mild cognitive impairment, which may be particularly useful in centres with less resources for more sophisticated biomarker analyses. The score may also be used to recruit patients at risk to develop dementia who can benefit from life style or other management interventions as well as for inclusion in clinical trials.

What´s in the near future for you?

I would like to continue working in the field of neurocognitive disorders both as a researcher and as a clinician on a psychiatric ward. I have a particular interests in cognitive symptoms in affective disorders. I am working as a resident doctor in psychiatry Southwest Huddinge, I hope to be able to combine my clinical training with clinical research.