New research from the journal Cognitive Behaviour Therapy points to a cognitive bias that might be involved in the maintenance of negative mood among people with depression. When compared to healthy controls, individuals with major depressive disorder (MDD) reported less happiness when recalling positive memories but more sadness when recalling bad memories.
Beck’s cognitive model of depression — one of the most prominent theories of depression — proposes that people with depression show a bias toward the processing of negative information about themselves over positive information about themselves.
Study authors Dahyeon Kim and K. Lira Yoon sought to build on a previous study that showed that people with elevated depressive symptoms differed in their emotional responses to personal memories compared to healthy individuals. For healthy subjects, the intensity of their positive feelings when remembering pleasant memories outdid the intensity of their negative feelings when remembering unpleasant memories. For individuals with depressive symptoms, the intensity of their emotional responses was the same whether they were remembering happy or unhappy memories from their personal histories.
In other words, healthy subjects’ emotional responses to memories faded more strongly for unpleasant (vs. pleasant) memories, while this was not true for those with depressive symptomology.
Kim and Yoon were motivated to re-explore this effect among a clinical sample. The researchers conducted interviews among 30 individuals with MDD and 46 control participants. During the interviews, subjects were asked to recall three events from their past: their happiest, saddest, and most anxious moments. After describing each memory, the participants answered two key questions. For the happy memory, they were asked to rate how happy they were when the event originally took place, and then how happy they are now reflecting on it. Similarly, for the sad memory, they rated how sad they were then and now. For the anxious memory, they rated how nervous they felt then and now.
Notably, the two groups did not differ in the intensity of their emotions experienced at the time of the event — this was true whether it was a happy, sad, or anxious memory. This finding implies that the two groups were recalling events of comparable emotional intensity. Nevertheless, in line with previous findings, ratings of happiness “now” were significantly lower among the MDD group compared to the control group. This was true even after controlling for how much time had passed since the event.
In short, the MDD group experienced less happiness when reflecting on happy memories and more sadness when reflecting on sad memories compared to the control group. The same effect was not found when it came to the anxious memories, suggesting that this differential fading of emotional responses to memories was specific to sad memories.
“Given their negative schemas (Beck, 2002), the saddest autobiographical memories (AMs) may align with the current worldview of individuals with MDD,” Kim and Yoon discuss. “Thus, these AMs may seem more relevant, resulting in more intense emotional responses in the MDD group. In contrast, the happiest AMs may contradict their current negative worldview, impeding the experience of more intense happiness in individuals with MDD.”
Kim and Yoon point out that previous studies have shown that recalling positive memories does not improve low mood among individuals with depression. The authors say that their findings offer insight into this effect. “Applied to treatment,” they say, “restructuring positive AMs, with the goal of increasing the happiness experienced from the recall, may be beneficial.”
The study, “Emotional response to autobiographical memories in depression: less happiness to positive and more sadness to negative memories”, was authored by Dahyeon Kim and K. Lira Yoon.
