Shrinking brain could aid diagnosis of depression
Parts of the brain shrink when people suffer clinical depression, according to scientists at the Biomedical Research Centre (BRC) for Mental Health at the Maudsley Hospital and King's College London's Institute of Psychiatry.
People suffering clinical depression (major depression) were shown to have reduced brain volume in a number of regions including the frontal lobe (responsible for planning, judgement and emotions), basal ganglia (movement) and hippocampus (memory). The study also suggests that the hippocampus returns to normal size when someone recovers or is in remission – suggesting that at least some of the changes are not permanent.
The changes to brain structure are distinct and in the future may allow clinicians to use an Magnetic Resonance Imaging (MRI) scan to identify and diagnose clinical depression and ensure the symptoms are not the result of another psychiatric or neurological illness – something that is currently clinical difficult.
Matthew Kempton, neuroimaging scientist at the BRC said: ‘Until now, we had no biological markers to distinguish between major depression and similar conditions such as bipolar disorder.’
‘Telling the difference between conditions is obviously very important as the diagnosis determines the treatment. In the case of clinical depression and bipolar disorder, one is treated with anti-depressants and the other is mainly treated with mood stabilisers such as lithium.’
The research was published today in Archives of General Psychiatry and was funded by both the National Institute for Health Research and the Wellcome Trust.
Researchers used a technique called ‘meta-analysis’ to combine results from 143 previous studies, each using Magnetic Resonance Imaging (MRI) to measure brain structure in people suffering depression.
The results were also compared to 98 studies of patients with bipolar disorder to make sure the changes in brain structure were specific to clinical depression. Comparing results to bipolar disorder, more reductions in gray matter volume were associated with clinical depression, whereas more abnormalities were identified in white matter in bipolar disorder.
Discovering when and how these changes in the brain occur will also help researchers to understand more about the causes of depression and ultimately how to treat it more effectively.
The study also found that the adrenal glands increased in volume in people with depression. The adrenal glands sit on top of the kidneys and produce cortisol - a hormone which is released in response to stress. Other research suggests that if this hormone is produced over a long time period it may shrink certain areas of the brain such as the hippocampusFor full paper: http://archpsyc.ama-assn.org/cgi/content/full/68/7/675