Associated Press Interview regarding the database and meta-analysis
featured in the Washington Post
Q) Which regions of the brain are different in size in people who have clinical depression (major depressive disorder)
A) In our meta-analysis of studies that have looked at brain structure in depression we found the following differences. It is important to state that the following are averages and that we see lots of variation in brain volumes in people who have depression.
Caudate volume was reduced by an average 3% of in people with major depressive disorder compared to people without the illness, the Putamen was reduced by 4%, the Globus Pallidus was reduced by 5%, Thalamus was reduced by 7%, Hippocampus was reduced by 6%, Frontal lobe was reduced by 4%, gray matter in the orbifrontal cortex was reduced by 8%, gyrus rectus was reduced by 16%.
There are regions normally found in the brain that are filled with cerebral spinal fluid (CSF) some of these regions were increased in volume in people who have major depressive disorder compared to those without the illness: the lateral ventricles were on average increased by 22%, and total cerebral spinal fluid volume was increased by 14%. In the discussion of our paper we also looked at gland called the adrenal gland which alos appears to be increased in volume in people with depression. For more detailed information please download the spreadsheet on the main page.
Q) What does "meta-analysis" mean?
A) Meta-analysis is a technique to combine the results of several studies. For example we hope to be able to understand how brain structure is affected in major depression by pooling different studies which have measured the same structure in patients with major depression compared to a control group. For more information see the meta-analysis page in wikipedia.
Q) I'm having problems downloading the database, what's wrong?
A) Some problems are caused by the internet browser trying to open the files rather than save them.
The largest file is 3Mb which may take time to download with some internet connections. If you are still having problems please contact us stating the name and version of your internet browser and the version of Excel you have. We will be happy to email you the files if all else fails.
Q) The Excel file opens but there are lots of cells saying #REF! and the graphs are not displaying properly.
A) You are probably using Excel 2003 or 2004, or an earlier version, although Excel may attempt to convert the files unfortunately this does not work. Downloading the freely available Excel viewer (follow the link on the MaND homepage) will allow you to see the database and meta-analysis functioning properly.
Q) Can a brain scan tell if you have depression?
A) No. With further research this may be possible in the future, but the differences we currently observe are small and can only be seen when we compare a large group of patients with depression to those without the diagnosis. However these changes may give use clues to what cause the illness and further research is needed to help us understand this.
Q) Why isn't our study included in your database?
A) The database only includes studies which have compared patients with major depressive disorder to a control group from 1980 to February 2010. We have excluded studies which combined patients with major depressive disorder with bipolar patients. We have also not included Voxel Based Morphometry Studies (VBM) as it is difficult to include these in a traditional meta-analysis. If you still think your study should have been included please contact us.
Q) Did you have direct access to all the MRI scans that were included in the meta-analysis?
A) No, we used volume measures published by the different research groups. For example when investigating total brain volume we used the published values from 28 different studies which reported the average brain volume in patients with depression and the average brain volume in a control group.
Q) I think I have found an error in your database.
A) An independent examiner checked every value entered into the meta-analysis so the chance of an error occurring is very small. However if you think you have spotted an error please contact us.
Q) How do I cite your paper / online database?
A) Thanks for asking, when citing the meta-analysis or online database the reference is:
Kempton MJ, Salvador Z, Munafò MR, Geddes JR, Simmons A, Frangou S, Williams SC (2011).
Structural Neuroimaging Studies in Major Depressive Disorder: Meta-analysis and Comparison With Bipolar Disorder.
Arch Gen Psychiatry. 2011 Jul;68(7):675-90.
Here are some made up examples of how you could cite us:
"In reviewing studies investigating the temporal lobe in depression we consulted the Major Depressive Disorder Neuroimaging Database (Kempton et al 2011). Increased volume of this structure was found by..."
"We combined the effect size found in our study with a meta-analysis of studies which have investigated the left putamen using the Major Depressive Disorder Neuroimaging Database (MaND, Kempton et al 2011). This gave a combined effect size of...."
"As we found a negative correlation between total gray matter volume and illness duration in our sample we performed a meta-regression between these variables using the Major Depressive Disorder Neuroimaging Database (Kempton et al 2011). The meta-regression was performed on 5 studies which measured total gray matter volume which reported mean illness duration. We detected a significant effect of illness duration on gray matter volume supporting our findings..."
Q) Do you have any other databases or websites?
A) Yes, I have been involved in creating:
-The Bipolar Disorder Neuroimaging Database which is similar in design to this website but looks at Bipolar Disorder
-The MRI Brain Segmentation Testing Protocol which is a collection of 312 freely available MRI images to test validity, reliability and sensitivity of segmentation algorithms
-ALVIN lateral ventricle segmentation, an SPM8 extension for segmenting the lateral ventricles which has been tested using the above testing protocol