American scientists from Washington University in St. Louis have discovered a new symptom that is often encountered by people with severe depression. It turned out to be uncontrollable wandering of thoughts. The study was published in the scientific publication Journal of Affective Disorders (JAD).
Mind wandering is the spontaneous shifting of attention from the task at hand or the external environment to internal thoughts or dreams. This usually occurs when people are engaged in routine or low-effort activities.
In people with depression, mind wandering tends to focus on negative thoughts, regrets, or worries, which contributes to a persistent low mood and feelings of hopelessness.
The study involved 106 adults under the age of 40 years. Of these, 53 were healthy and had no history of mental illness, while the other 53 were diagnosed with major depressive disorder.
The study authors provided participants with a portable electronic device with Experience Sampling Program 4.0 installed. Over the course of 7–8 days, participants received random prompts eight times daily to report their current experiences, for a maximum of 56 prompts over the entire period. On average, participants completed about 43–44 prompts, with a similar number in both groups.
The results showed that participants with major depressive disorder reported mind wandering twice as often as healthy controls. These individuals reported mind wandering in 37% of prompts, compared to only 17% for healthy individuals. Differences in the frequency of mind wandering among people with major depressive disorder were much greater than among healthy controls.
Mind wandering among people with major depressive disorder was also much more likely to have a negative tone. These people reported that their mind wandering had a negative valence 42% of the time, compared to just 10% among healthy participants.
