DEPRESSION is toxic to the brain and reduces grey-matter volume in several key regions, scientists have established for the first time in a three-year follow-up examination of patients admitted to a psychiatric ward.
Study leader Thomas Frodl said the findings meant early diagnosis of depression was critically important and treatment - with antidepressants or psychotherapy - should begin immediately after a person became ill. Prompt treatment might prevent permanent brain damage, he said.
Dr Frodl took high-resolution images of the brains of 38 patients when they were first admitted to hospital with serious depression, and again one, two and three years later. He found those who remained ill experienced more grey-matter loss than those whose depression got better and 30 healthy people whose brains were also scanned.
It is the first time such changes have been observed over time, and the study, published yesterday in the journal Archives of General Psychiatry , revealed those whose brains were worst affected were less likely to make a good recovery.
Grey-matter loss in the hippocampus, prefrontal cortex and anterior cingulum areas of the brain "seems to be associated with more severe outcome of depression", said Dr Frodl, of the Ludwig Maximilians University, in Munich.
Previous research has found people with depression have smaller brain volumes in some of these areas, but Dr Frodl's work demonstrates for the first time that brain changes occur in tandem with depression and are linked to its severity. It also confirms animal research that shows high levels of stress hormones cause brain damage.
Leanne Williams, professor of cognitive neuropsychiatry and director of the Brain Dynamics Centre at Westmead Hospital, said the study highlighted "the importance of considering brain [changes] to support clinical decisions about depression and its treatment". She said it would be valuable to repeat the research in younger people - the average age in the German study was 46 - and follow them over time to investigate links between brain changes and the onset of depression.
Perminder Sachdev, professor of neuropsychiatry at the University of NSW, said the findings were consistent with observations that "patients with depression do develop problems with cognition that persist even when the depression has improved". The brain areas identified by Dr Frodl were responsible for planning and organisational ability, motivation, memory and learning, said Professor Sachdev. Any ot them can be affected by depression. The results also tallied with evidence that taking antidepressants could help regenerate brain cells.
But Professor Sachdev said the scanning technique used by Dr Frodl - known as voxel-based morphometry - could be unreliable, and if stress hormones were implicated, it was unclear why they did not also adversely affect other brain regions.
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