Memory loss due to stress: causes and symptoms

Whether it occurs transiently or sustainably, the physiological stress response alters the memory, causing difficulties to retain new information and to recover memories already consolidated.

Nevertheless, the effects of stress on memory can be somewhat contradictory and they differ depending on whether we are talking about acute or chronic stress.

Link Between Stress And Memory Loss

When the demands of the situation in which we find ourselves exceed our physical and/or cognitive capacities, our body activates the stress response. This consists of the release of glucocorticoids, stress hormones, into the bloodstream.

Glucocorticoids cause different effects in the body, among which are the increase in heart rate and blood pressure. respiratory system, the reduction of gastrointestinal activity and the release of stored glucose reserves in order to use them as power source.

If its concentration is excessive, glucocorticoids, among which the cortisol, can have a negative effect on the functions of the

hippocampus, brain structure that is associated with the formation and retrieval of memories. This is partly because glucocorticoids redirect glucose from the hippocampus to nearby muscles.

Two types of stress have been described depending on their origin: extrinsic and intrinsic.. Extrinsic stress is caused by non-cognitive factors, such as those that come from a situation determined, while the intrinsic is related to the level of intellectual challenge that requires a task. Some people have chronic intrinsic stress.

Stress interferes with both our ability to retain new information and to retrieve memories and knowledge, causing memory loss. In addition, extrinsic stress seems to affect spatial learning. In the following sections we will describe these effects in more detail.

Yerkes-Dodson's law: the inverted U

The Yerkes-Dodson law states that stress does not always interfere negatively with cognition., but rather a moderate degree of brain activation improves memory and performance on intellectual tasks. Instead, the excessive increase in stress levels worsens cognitive functions.

This gives rise to the so-called "inverted U effect": if our body responds to environmental demands with mild or moderate stress responses, the effectiveness of our Productivity increases until it reaches a threshold (the ideal activation point) from which performance decreases progressively and losses of production occur. memory.

Overly intense stress responses interfere with the performance of intellectual tasks because they are associated to physical and cognitive symptoms such as concentration difficulties, tachycardia, sweating, dizziness or hyperventilation.

Effects of acute or transient stress

When we find ourselves in a stressful situation, our attention is focused on the most salient stimuli, while we pay less attention to the rest; This phenomenon is known as “tunnel vision” and it facilitates the consolidation of some memories while interfering with others, causing memory loss.

Acute stress can have beneficial effects on some types of memory, but only under certain conditions. In this sense it is worth mentioning the Yerkes-Dodson law again; besides, some studies have shown that glucocorticoids enhance the formation of new memories but worsen the recovery of others already existing.

In addition, emotionally relevant stimuli are better remembered if the stress response has occurred before, if the information retrieval takes place shortly after encoding and if the recall situation is similar to that of learning.

Other research suggests that, under stressful conditions, we learn and remember information and situations that cause us emotional distress to a greater extent. This fact is associated with the congruence effect of the mood described by Gordon H. Bower, which describes similar results in relation to the depression.

Consequences of chronic stress

The stress response not only involves changes in memory at the time it occurs, but if it is maintained chronically it can cause long-term damage to the brain. Since the organism consumes many resources and reserves in the activation of these physiological processes, chronic stress is significantly more damaging than acute stress.

After acute or transitory stress situations, our body recovers homeostasis, that is, physiological balance; instead, chronic stress prevents the body from reaching homeostasis again. Therefore, if stress is maintained, it unbalances the body's responses.

From a physiological point of view, this facilitates the appearance of symptoms such as abdominal pain, back pain and headache, chronic difficulties concentrating and falling asleep or staying asleep, panic attacks, etc. In addition, continued stress is associated with social isolation, depression and the development of cardiovascular diseases.

As for memory loss, chronic stress increases the risk of dementia in older people. These effects are probably related to glucocorticoid activity in the hippocampus and other brain regions on which memory and cognition in general depend.