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Depression: Slow decisions could be a sign of relapse
The number of people with depression has been rising steadily for years. Most of those affected experience more than one depressive episode over the course of their lives. According to a new study, slow decisions could indicate such a relapse.
According to a communication from the Swiss National Science Foundation (SNSF), the probability of people suffering from depression after stopping antidepressants can be partially predicted. Those who experience such a relapse often take longer to decide how much effort they want to spend on a reward.
Depressive phases come and go
The number of people with depression has increased significantly in recent years worldwide. A recent study by the Robert Koch Institute (RKI) showed that more people are affected in Germany than in other EU countries.
The disease is often recurring: Depressive phases come and go. It is known from various studies that treatment should continue beyond symptom resolution to reduce the risk of relapse. Unfortunately, this does not seem to have any impact on the risk of relapse after stopping the medication.
“An estimated 30 percent of those affected relapse in the first six months after weaning. That is a very high percentage. So far, there is no established instrument that can be used to assess this risk, ”explains psychologist Isabel Berwian.
In a longitudinal study supported by the SNSF and published in the journal "JAMA Psychiatry", the researcher was able to show that certain predictions about the risk of relapse in depression are possible.
The scientist, now a postdoctoral researcher in the field of translational neuromodeling at the University of Zurich and ETH Zurich, has observed how those affected make decisions during the remission period.
Inflate the balloon and win points
For the study, the research team of Quentin Huys, then a researcher in computational psychiatry and a specialist in psychiatry and psychotherapy, recruited patients with recurrent or severe depressive illness who were in the remission phase.
The participants had no or almost no symptoms, but were still taking antidepressants. Regardless of the study, they had already decided to stop taking the appropriate medication.
All subjects received a task that could be used to measure their willingness to make an effort depending on the level of reward.
To measure the decision time, they had to press a button on the computer to score points. They said they had five seconds to choose between two alternatives that required more or less effort.
The participants could either press the button 20 times for one point, or 100 times for three to seven points depending on the current task. After the decision, they each had 40 seconds to press the button as many times as they chose.
They could then inflate a virtual balloon that would burst if they had pressed enough times. The participants completed this task 60 times each.
As stated in the communication, this experimental setup was chosen because the specialist literature shows that people with depression are typically less willing to try to reward themselves. The scientists wanted to go one step further and investigate whether conclusions can be drawn about a potential relapse.
Decision time for people with depression was longer
The data were collected between July 2015 and January 2019 in 123 patients and 66 healthy comparators in Zurich and Berlin. Everyone who had depression had two tasks: the first time before stopping medication, the second time either before or after stopping medication.
In addition, all participants were followed up for six months after the study to see if they had a relapse.
The results showed that the decision time for those suffering from depression was longer than that of the people in the comparison group (on average 1.77 or 1.61 seconds). In addition, it was even longer within the patient groups for those who relapsed after weaning (1.95 seconds on average).
The experts were able to show that two out of three people correctly predict whether they will relapse due to the decision time.
The least strenuous option chosen
A calculation model was used to find out which mechanisms play a role in this task. It was found that the option chosen (small effort for a small reward or greater effort for a larger reward) is a differentiator between the formerly depressed person and the healthy person:
The former more often chose the least strenuous option. The researchers believe that this is an indication that the depression is still asymptomatic in the background.
The model has also shown that people who have experienced a depressive phase are more likely to avoid exertion.
“Imagine that you are already in bed one evening. Then acquaintances call and ask if they will come and eat you an ice cream in the city, ”explains Isabel Berwian.
“A healthy person will probably get up and go. A person who has had a depressive episode is more likely to stay in bed. Even if she liked the activity, it would seem like too much effort. ”
Findings for application in practice are not yet ripe
However, even though the study has shown that the decision-making time enables certain predictions to be made regarding the risk of relapse, these findings are not yet ripe for practical application.
“This indicator is promising, but we cannot yet claim that we have found“ the ”solution. Our results would have to be validated on a larger sample because ours was relatively small, ”says Isabel Berwian. This is a challenge for the researchers because it is difficult to find patients for such studies.
The study was carried out at the Translational Neuromodeling Unit of the University of Zurich and the ETH Zurich and at the Psychiatric University Clinic Zurich in collaboration with the Charité University Hospital in Berlin.
The German Depression Aid Foundation points out on its website that those affected can do something themselves to reduce the risk of another depression. This risk can be reduced by 70 percent through measures to prevent relapse.
According to the experts, this includes regular medication, psychotherapy and specific activities.
In this context, sufficient exercise, enough sleep and a healthy and balanced diet are important. (ad)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
- Swiss National Science Foundation (SNSF): Depression: Slow decisions could be a sign of a relapse, (accessed: February 22, 2020), Swiss National Science Foundation (SNSF)
- Isabel M. Berwian, J. Wenzel, A.G. E. Collins, E. Seifritz, K. Stephan, H. Walter, Q.J.M. Huys :: Computational Mechanisms of Effort and Reward Decisions in Patients With Depression and Their Association With Relapse After Antidepressant Discontinuation; in: JAMA Psychiatry, (published: February 19, 2020), JAMA Psychiatry
- German Depression Aid: Relapse Prevention, (accessed: February 22, 2020), German Depression Aid