- Depressed mood can colour the way we remember our personal past and lead to biased memory for negative events.
- Memories of negative past events may become key reference points through which people with depression view themselves.
- When people with depression remember negative past events they may attach negative meaning to them and become highly self-critical.
- Different therapies can help reverse the downward spiral of depressed mood, negative memories, and self-criticism.
Most people experience passing periods of sadness or negative feelings in their everyday lives. Normally, these feelings are relatively short-lived and do not have a long-lasting impact on how people view themselves and the world. However, during depression, negative thoughts and feelings of sadness may become all-encompassing and end up colouring every aspect of people’s lives: past as well as present. This is reflected in the tendency of depressed individuals to more easily remember negative than positive past events, while healthy individuals typically remember more positive than negative events from their past. Unpleasant feelings related to negative events may also fade slower than normal, and thinking about negative events causes heightened levels of distress and negative emotions during depression. This heightened salience of negative past events and difficulties dealing with these memories may profoundly impact the everyday mood of individuals suffering from depression and interfere with recovery from depression.
But why do negative memories become more salient during depression? How do these memories maintain depression? And is there anything that can be done to make negative memories less salient and distressing, and heighten memory for positive past events?
1. We remember events that are aligned with our present mood
Our autobiographical memory can be understood as an enormous network of representations of events from our own life. In this network, representations of events that share characteristics are linked together by associative pathways. This can be of huge help in everyday life. For example, in everyday life, we encounter multiple situations that are slightly different from any situation we have encountered in our past. If we had to learn from scratch how to deal with every new situation, this would require a great deal of time and cognitive resources. Luckily, because our memory links together conceptually related events, we can relatively easily recall and utilize the knowledge acquired from related past situations to help us deal with new situations, even if they are not exactly the same.
However, this heightened accessibility of related events also means that, if we are in a specific mood or state, we will be more likely to remember past events that are consistent with that mood than memories that are not aligned with our current mood. During depression, when the prevailing feeling is one of profound sadness, this prompting of mood-aligned material might lead to excessive activation of memories of negative past events. This excessive activation of negative memories may in turn lead to a further mood deterioration, and ultimately result in a downward spiral where negative memories and moods reinforce each other and maintain a depressed mood.
2. Negative memories become more engrained in our identity
Memories of past events play an important role in defining our identity and life stories. Healthy adults generally view positive past events as more central to their identity and life stories than negative past events. This greater integration of positive, relative to negative, life events in one’s identity has a self-enhancing effect and is associated with greater life satisfaction. When people suffer from depression, however, they often view negative past events as more central to their life stories. This means that, during depression, negative life events may become key reference points through which people view themselves and their present life situation, and may create a more negative outlook on the future. This is likely to maintain a depressed mood through reinforcing a negative view of the world and oneself.
3. We become harsh evaluators of ourselves and our past
One of the key characteristics of depressive thinking is rumination or a repetitive and evaluative focus on one’s thoughts and emotions. These evaluations are often highly negative and self-critical and may become so habitual during depression that they seem almost impossible to escape. Often, these evaluations may seem logical to people suffering from depression. Indeed, many people with depression report using rumination as an attempt to cope with or understand their depression and their past. However, in reality, the negative and self-critical nature of these evaluations means that they often lead to a mood worsening and a heightened sense of hopelessness. This is also true for the evaluations that people with depression make about their memories of negative past events.
When people with high levels of depression have intrusive memories of unpleasant past events, they are more likely to attach negative meaning to these memories, such as thinking that something is wrong with themselves or that they are inadequate, compared to people with low levels of depression. They also think more about what they could have done differently and worry that the event could happen again. These negative, self-focused evaluations of past events may lead to heightened emotional distress when thinking about an unpleasant past event, and as such have a considerable impact on the everyday mood and well-being of individuals with depression.
4. How can the spiral be reversed?
While it is clear that depression negatively colours the way we view our past and that this can lead to a negative spiral where depressed mood is maintained, this does not mean that there is no way of reversing the spiral. Researchers and psychologists have developed several techniques and therapies that may reduce intrusive negative memories or help people with depression deal with or relate to their memories in more adaptive ways. One technique that may help people deal with upsetting memories is ‘Imagery Rescripting.’ When used in therapeutic settings to deal with upsetting memories, this technique involves reliving the upsetting memories in our minds and then rewriting them in ways that make them less upsetting. For example, we may imagine comforting or standing up for our past selves against a bully. This may help us view our past selves with greater compassion and dignity, rather than viewing ourselves as worthless or powerless. Working with upsetting representations of past events in this way may also reduce their intrusiveness because they are replaced by less disturbing representations through the process of imagery rescripting.
Other therapies that may help people deal with negative memories are therapies that encourage people to relate to their mental content in new and more adaptive ways, such as mindfulness-based cognitive therapy (MBCT). One of the key skills encouraged by these therapies is the ability to mentally step back and perceive our mental content in an open, accepting, and non-judgmental manner. This may help us become more accepting of the experience of having upsetting memories and reduce automatic and negative evaluations when we think about our past. By changing how we evaluate and relate to our negative memories, the negative mood impact of these memories may dampen.
In addition to these techniques that may reduce intrusions and negative evaluations of upsetting memories, researchers have also identified a technique that may help people with depression access positive memories more easily. This technique includes utilizing the ‘method-of-loci’ technique. This involves individuals imagining a familiar route or location consisting of rich and vivid imagery to which they can attach memories of positive events, as well as rich and vivid elaborations of the positive events. The rich imagery and elaboration encouraged by this technique may both improve the ability to recall positive memories in people with depression and have beneficial effects on mood.
Although depression can lead people down a spiral of heightened access to negative memories, self-critical evaluations, and mood deterioration, there are ways of reversing this spiral. Different therapies and techniques may help people with depression relate to their upsetting memories in less judgmental and more self-affirming ways, through rescripting and encouraging a more accepting stance towards the memories and oneself. Furthermore, available techniques that can make it easier to access rich and vivid representations of positive past events may increase positive emotions in individuals with depression. These changes can have a powerful impact on the everyday mood and perceptions of people with depression and help lift them out of a negative depressive spiral.
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