The brains of people with recurrent depression have a significantly smaller hippocampus - the part of the brain most associated with forming new memories - than healthy individuals, a new global study of nearly 9,000 people reveals.
Published in Molecular Psychiatry, the ENIGMA study is co-authored by University of Sydney scholars at the Brain and Mind Research Institute.
People with depression were shown to have reduced hippocampus volume compared to non-depressed people.
The research is the largest international study to compare brain volumes in people with and without major depression. It highlights the need to identify and treat depression effectively when it first occurs, particularly among teenagers and young adults.
Using magnetic resonance imaged (MRI) brain scans, and clinical data from 1,728 people with major depression and 7,199 healthy individuals, the study combined 15 datasets from Europe, the USA and Australia.
Major depression is a common condition affecting at least one in six people during their lifetime. It is a serious clinical mood disorder in which feelings of sadness, frustration, loss, or anger interfere with a person's everyday life for weeks, months or years at a time.
The key finding that people with major depression have a smaller hippocampus confirms earlier clinical work conducted at the BMRI. In this study, the key finding was largely explained by subjects with recurrent depression.
People with recurrent depression represented 65 per cent of study subjects with major depression.
People with an early age of onset of major depression (before the age of 21 years) also had a smaller hippocampus than healthy individuals, consistent with the notion that many of these young people go on to have recurrent disorders.
However, people who had a first episode of major depression (34 per cent of study subjects with major depression) did not have a small hippocampus than healthy individuals, indicating that the changes are due to the adverse effects of depressive illness on the brain.
"These findings shed new light on brain structures and possible mechanisms responsible for depression," says Associate Professor Jim Lagopoulos of the University of Sydney's Brain and Mind Research Institute.
"Despite intensive research aimed at identifying brain structures linked to depression in recent decades, our understanding of what causes depression is still rudimentary.
"One reason for this has been the lack of sufficiently large studies, variability in the disease and treatments provided, and the complex interactions between clinical characteristics and brain structure."
Commenting on the clinical significance of the findings, Co-Director of the Brain and Mind Research Institute, Professor Ian Hickie says: "This large study confirms the need to treat first episodes of depression effectively, particularly in teenagers and young adults, to prevent the brain changes that accompany recurrent depression.
"This is another reason that we need to ensure that young people receive effective treatments for depression - a key goal of our Centre of Research Excellence in Optimising Early Interventions for Young People with Emerging Mood Disorder.
"This new finding of smaller hippocampal volume in people with major depression may offer some support to the neurotrophic hypothesis of depression," adds Jim Lagopoulos.
"This hypothesis argues that a range of neurobiological processes such as elevated glucocorticoid levels in those with chronic depression may induce brain shrinkage.
"Clearly, there's a need for longitudinal studies that can track changes in hippocampal volume among people with depression over time, to better clarify whether hippocampal abnormalities result from prolonged duration of chronic stress, or represent a vulnerability factor for depression, or both," he said.
Professor Ian Hickie, Co-Director of the Brain and Mind Research Institute, +61 438 810 231
University of Sydney:
Kobi Print: +61 481 012 729, email@example.com
Jocelyn Prasad: +61 434 605 018, firstname.lastname@example.org
Kobi Print | EurekAlert!
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences