A study on a large sample of patients found chronic, long-lasting depression to be associated with reduced brain volume. The reduced volume was found in brain regions relevant for planning one’s behavior, focusing attention, thinking, learning and remembering and also in regions relevant for regulating emotions. The study was published in Neurobiology and Treatment of Depression.
Depression, also called major depressive disorder, is a mood disorder that causes a persistent feeling of sadness and loss of interest. It changes the way a person feels, thinks and behaves. For many people suffering from it, depressive episodes become a recurring event. More than half of patients with depression experience a relapse after 2 years and the probability of recurrent depressive episodes rises to 90% after 3-4 episodes. Studies have indicated that recurring depressive episodes might be linked to structural changes in the brain, but the existing results are not uniform.
Ms. Hannah Lemke and her colleagues analyzed the data of 681 patients from the Marburg-Muenster-Affective-Cohort Study (MACS) in order to better link properties of the course of depressive disorder with specific changes in the brain structure. Patient data were collected at two sites in Germany – Muenster and Marburg.
Patients participated in a clinical diagnostic interview (Structured Clinical Interview-I) that focused on the number and duration of hospitalizations and the duration of the disease, completed an assessment of depressive symptoms (Hamilton Depression Rating Scale, HDRS) and the current medication regime, and underwent brain imaging using magnetic resonance imaging and voxel-based morphometry.
The results showed that an adequate description of the course of a depressive disorder needs to focus on two components – hospitalization i.e., the number and duration of lifetime hospitalizations, and duration of illness i.e., the time since the first psychiatric episodes and the number and duration of lifetime depressive episodes.
These two components were found to be linked with specific changes in the brain structure. Longer durations of illness were associated with lower volumes of grey mass in the left hippocampal and dorsolateral prefrontal cortex regions of the brain. Higher hospitalization scores were associated with significantly decreased gray mass volume in the dorsolateral prefrontal cortex (on both sides) and left insula regions of the brain.
An important strength of this study is that it involved a very large and diverse group of patients suffering from depression. However, the duration of illness assessment was based on self-reports, which can be affected by difficulties of remembering the previous course of illness. Hospitalization for depression is done when symptoms of depression are severe or when suicidal ideas/behavior is present.
This means that the association between brain structure alterations and the hospitalization component of depression course may be the result of severity of depressive symptoms and not of the hospitalization itself. Authors conclude that stress-related mechanisms may be underlying the described effects.
The study, “Association of disease course and brain structural alterations in major depressive disorder”, was authored by Hannah Lemke, Lina Romankiewicz, Katharina Förster, Susanne Meinert,Lena Waltemate, Stella M. Fingas, Dominik Grotegerd, Ronny Redlich, Katharina Dohm, Elisabeth J. Leehr, Katharina Thiel, Verena Enneking, Katharina Brosch, Tina Meller, Kai Ringwald, Simon Schmitt, Frederike Stein, Olaf Steinsträter, Jochen Bauer, Walter Heindel, Andreas Jansen, Axel Krug, Igor Nenadic, Tilo Kircher, and Udo Dannlowski.