Title:Depression in Dementia or Dementia in Depression? Systematic Review of Studies and Hypotheses
VOLUME: 17 ISSUE: 1
Author(s):Agnieszka Brzezińska, Julius Bourke, Rayito Rivera-Hernández, Magda Tsolaki, Joanna Woźniak and Jakub Kaźmierski*
Affiliation:Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Lodz, Centre for Psychiatry, Wolfson Institute for Preventive Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University London, London E14NS, Department of Psychiatry, Psychology, Legal Medicine and History of Medicine, University of Salamanca, Salamanca, 3rd Department of Neurology, Aristotle University of Thessaloniki, Thessaloniki, Greece, “George Papanicolaou” Hospital, Thessaloniki, Central Clinical Hospital of Medical University of Lodz, Lodz, Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Lodz
Keywords:Alzheimer's disease, depression, dementia, risk factor, comorbidity, common genes, antidepressants.
Abstract:The majority of research works to date suggest that Major Depressive Disorder (MDD) is a
risk factor for dementia and may predispose to cognitive decline in both early and late onset variants.
The presence of depression may not, however, reflect the cause, rather, an effect: it may be a response to
cognitive impairment or alters the threshold at which cognitive impairment might manifest or be detected.
An alternative hypothesis is that depression may be part of a prodrome to Alzheimer’s Disease
(AD), suggesting a neurobiological association rather than one of psychological response alone. Genetic
polymorphisms may explain some of the variances in shared phenomenology between the diagnoses, the
instance, when the conditions arise comorbidly, the order in which they are detected that may depend on
individual cognitive and physical reserves, as well as the medical history and individual vulnerability.
This hypothesis is biologically sound but has not been systematically investigated to date. The current
review highlights how genetic variations are involved in the development of both AD and MDD, and the
risk conferred by these variations on the expression of these two disorders comorbidly is an important
consideration for future studies of pathoaetiological mechanisms and in the stratification of study samples
for randomised controlled trials.
