Affiliations: Saint-Joseph University of Beirut, Lebanon
Journal reference: https://doi.org/10.1016/j.tics.2014.06.010
Summary: In this article, authors explored how disruption of autobiographical memory could play a crucial role in the triggering, maintenance, and recurrence of depression.
Depression is often discussed yet rarely properly understood. It is a mental disorder characterized by constant fatigue, feelings of guilt, worthlessness, sadness, impaired concentration, and sometimes suicidal thoughts. These symptoms interfere with productivity and lead to a decrease in quality of life. It is among the leading causes of disability worldwide, with many individuals experiencing multiple episodes over the course of their life.
There are different approaches to understanding certain disorders, but with depression research has shown that our schemas, or internal blueprints of our expectations and views of the world contribute to depressive symptoms.
There is a concept called the “negative cognitive triad”, which is a negative internal representation of the self, the world and the future. These negative representations feed into each other. This triad is believed to be the root of the pessimistic views and thoughts of individuals with depression. The negative beliefs that influence their perception of their internal and external worlds serve to further ingrain and support the foundation that drives the disorder.
There is another factor that is thought to play a crucial role in the triggering, maintenance, and recurrence of the disorder. This factor is the disruption of autobiographical memory. This mental process relates our personal memories to our knowledge of our self and past experiences that define our identity. The autobiographical memory of individuals with depression has been found to be affected in four core ways; biased recollection of negative memories, impoverished access and response to positive memories, reduced access to the specific details of the personal past, and lastly the rumination and avoidance around autobiographical memories.
Biased recollection of negative memories
Those suffering with depression tend to default to unpleasant memories when asked to recall a random memory. Moreover, they interpret ambiguous scenarios and experiences according to their negative beliefs, which sometimes distorts otherwise neutral events into more negative experiences. They also experience intrusive memories of specific traumatic and distressing events more often than those without depression. This negative recall bias enforces their negative beliefs about the world and themselves, hence contributing to the maintenance of depressive symptoms.
Impoverished access and response to positive memories
The biased recall of negative memories is compounded with a difficulty in remembering positive memories. Indeed, the reason why depressed individuals favor negative memories is due to their struggle in retrieving positive material. Negative information is more easily mentally accessible and given a higher priority than positive or neutral information. If they do remember positive material, these memories are significantly less vivid and less emotionally charged than negative ones, and have little impact on improving mood. Additionally, these memories could even be harmful to the depressed individual, as they can lead to comparing past happier times to the perceived bleak present reality. This can kick-start the process of rumination leading to the vicious cycle of negative thinking.
Reduced access to the specific details of the personal past
Another feature specific to the autobiographical memory of individuals with depression is the overgeneralization of past memories. For example, when remembering their college years, they would disregard or rather forget joyful moments. Overall, individuals with depression will usually not go into much detail when narrating past personal events. Their memories are categorized into general, often negatively valenced themes that capture patterns and regularities across many personal experiences. This categorical processing overrides detailed memory, leading to more general negative recollections of the past. The scarcity of positive themes in autobiographical memory is a cardinal sign of depression.
Rumination and avoidance around autobiographical memories
The recollection of past experiences can be painful and upsetting to individuals with depression. As a result of this emotional distress, past personal events are sometimes suppressed and avoided. However, this is not an effective coping technique as suppression can lead to intrusions. Intrusive thoughts about negative memories can be quite upsetting as they arise spontaneously and without warning.
Interestingly studies have shown that individuals with depression tend to recall memories in the form of “mental images” rather than “verbal narratives”. This allows them to adopt the position of an observer rather than a participant. This in turn serves as a coping mechanism to reduce the impact of unwanted emotions. This tendency is also present with positive memories, and this can be unhelpful as it sets a distance between themselves and pleasant memories that could potentially aid in mood regulation.
The CaR-FA-X is a model for how autobiographical memory processing operates in individuals with depression. To summarize, there are three processes: “capture and rumination” (CaR) which is the effort it takes to access one’s memories that are cemented by generalizing negative themes, “functional avoidance” (FA) which is the repeated avoidance of recalling specific distressing details in one’s autobiographical memory, and “impaired executive control” which defines the inability to overcome these dysfunctional processes because of the weakened executive functions ̶ mental skills like planning, flexible thinking and working memory ̶ linked to depression.
Researchers have gathered a few ways to treat these dysfunctional processes and ease the symptoms of depression. These techniques are part of the cognitive behavior therapy approach, which aims to identify biases in thinking and schemas, and modify them to make them more “adaptive and functional”. Among these techniques are the Method of Loci. This method consists of visualizing spatial environments one is familiar with to mentally associate pieces of information to them ̶ and the “Memory Specificity Training” (MEST) which consists of training patients to be more specific when trying to recall memories in order to avoid unwanted over general recollection. These techniques aim to rescript negative autobiographical memories to reduce their impact on mood.
To conclude, the four core domains of difficulty in depressed individuals’ autobiographical memory are what define and perpetuate depressive episodes. Depression’s impact on memory should not be downplayed. It is important to know the mechanism of its functioning in order to better assist and understand depressed individuals. Therefore, we have briefly explored two main promising techniques for treating this disorder.