A study of a large sample of patients found that chronic, long-term depression is associated with reduced brain volume. Decreased volume was found in areas of the brain associated with planning one’s behavior, focusing attention, thinking, learning and memory, as well as areas related to emotion regulation. 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 who suffer from it, depressive episodes become a recurring event. More than half of depressed patients experience a relapse after 2 years, and the likelihood of recurrent depressive episodes increases to 90% after 3-4 episodes. Studies have shown that repeated depressive episodes may be associated with structural changes in the brain, but existing results are not uniform.
Hannah Lemke and her colleagues analyzed data from 681 patients from the Marburg-Muenster-Affective-Cohort (MACS) study in order to better link properties of the course of depressive disorder to specific changes in brain structure. Patient data were collected at two locations in Germany – Muenster and Marburg.
Patients participated in a clinical diagnostic interview (Structured Clinical Interview-I) that focused on number and duration of hospitalizations and duration of illness, completed an assessment of depressive symptoms (Hamilton Depression Rating Scale, HDRS), and current treatment regimen. and underwent brain imaging using MRI and voxel-based morphometry.
The results showed that an adequate description of the course of a depressive disorder must focus on two components: hospitalization that is, the number and duration of hospitalizations throughout their lifetime, and duration of illness ie, time since first psychiatric episodes and number and duration of lifetime depressive episodes.
These two components were found to be associated with specific changes in brain structure. Longer duration of illness were associated with lower gray matter volumes in the left hippocampus and dorsal prefrontal cortex regions of the brain. Higher hospitalization scores were associated with significantly reduced gray matter volume in the dorsal prefrontal cortex (both sides) and left insular brain regions.
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 disease assessment was based on self-reports, which may be affected by difficulties in recalling the previous course of the disease. Hospitalization for depression is done when symptoms of depression are severe or when suicidal ideation/behavior is present.
This means that the association between changes in brain structure and the hospitalization component of the course of depression may be a result of the severity of depressive symptoms rather than the hospitalization itself. The authors conclude that stress-related mechanisms may be behind the described effects.
The study, “Correlation of disease course and structural brain changes 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 and Tilonski, .