“People who have already experienced two or more depressive episodes perform abnormally slowly common cognitive tasks that require attention, concentration and speed in particular.” These are the conclusions of a study that Inserm researchers have just published in the scientific journal European Neuropsychopharmacology.
This study directed by Pr Philip Gorwood, from the Center of Psychiatry and Neurosciences of the Sainte-Anne Hospital (Paris) is the first which manages to show so simply the “neurotoxic” effects of depression. It also confirms the daily observations of doctors and the conclusions of previous epidemiological studies, namely that the Depression is a disease that gets worse over time.
“In addition, this study could also provide a possible explanation for this vicious circle: the more depressive episodes I have experienced, the more likely I am to relapse. If the speed and efficiency are increasingly impaired as relapses, we conceive that it is more difficult to adapt to new situations “explains the doctor.
5 times longer to do a simple test
For this study, the researchers assessed the cognitive abilities of 2,000 patients who had experienced between 1 and 5 episodes of depression during their lifetime. They measured the speed of carrying out a simple test which consists in connecting numbered circles and placed in disorder on a sheet. This test was performed twice: once during depression and a second time when the patients were in remission.
“Just after a first depression, the time needed to perform this test is 35 seconds. Same after the second episode. But in people who have already experienced 2.3 or more depressive episodes, this time is considerably longer and passes from 35 to 80 seconds, including in people who have recovered” adds the doctor.
For the Inserm researchers, these alterations in cognitive abilities could be considered as an argument in favor of “cognitive remediation” therapy, widely used for treat schizophrenia or addictions, but little used to remedy the disorders caused by depression.
