four questions to Francis Eustache

On the occasion of Blue Monday on January 16, considered the most depressing day of the year, the B2V Memories Observatory returns to the links between memory and depression. Can this cause memory loss? Is it possible to “repair” once the depressive episode is over? Do we have enough hindsight to know the impact of the pandemic on our brain? Francis Eustache, neuropsychologist and president of the Scientific Council of the B2V Memories Observatory has decided to enlighten us on these issues.


Can depression cause memory impairment or malfunction?

Depression is a generic term that encompasses very different situations. It is a young or old person, it consists of a single or recurring episode, it is simple or accompanied
other mental disorders, the most common of which is anxiety (these are comorbidities).

The depressed subject presents a sad mood, loss of interest, decreased vitality and activity; this decrease in speed is felt as a source of fatigue and the depressed person finds it difficult to
wake up in the morning.

The person suffers from a lack of confidence and self-esteem, guilt, or worthlessness. Suicidal ideation is a worrisome symptom, with a suicidal risk proportional to the severity of the depression. Depression alters sleep, libido, eating: weight is a good monitoring element.

Depression is not as such a memory disease. However, the change in mood can modify the functioning of memory (memory capture and retrieval), make it difficult to concentrate and cause ideomotor retardation.

In addition, insomnia alters the quality of memory consolidation, which is no longer reinforced during sleep. This dysfunction is very different from Alzheimer’s disease, which, by altering anatomical elements of the memory circuit, leads the patient to forget entire stretches of his life (old memories), to not be able to record new information and finally to not project himself into the future. future (remember, for example, what to do the next day).

The depressed person has difficulty remembering information spontaneously. In memory tests, this corresponds to the conditions of free recall or spontaneous recall. It is a functional access problem that can be improved with hints (the searched word is that of an animal) and in life by the context or a little help (find the paper on which we marked the RV time). On the contrary, the indices do little or nothing to help the patient suffering from Alzheimer’s disease.

In addition, the content of memories can be modified by dark thoughts and these, in turn, invade the thoughts of the depressed person, resulting in a vicious circle and worsening morale. The distortion of the perception of time and in particular the projection into the future with the impression of an accelerated time is also often reported.

Biographical episodic memories are scarce, dull and “overgeneralized”, the depressive withdrawn into himself is invaded by negative emotions where sadness predominates.

How does depression change our brain? Once the depressive episode is resolved, does the memory become effective again?

Research in neurosciences, using functional brain imaging methods, measures under certain conditions variations in metabolism corresponding to clinical descriptions and dysfunction of the circuits that connect the prefrontal regions (in front of the brain) and the hippocampus, involved in declarative memory, attention, concentration, working memory and processing speed.

These modifications concern the regions underlying the control functions: encoding and retrieval, resulting in insufficient free recall memory tests. These observations are made in the context of research on groups of patients.

Imaging tests are of no interest in monitoring a depressed person: magnetic resonance imaging is normal (without structural lesion) and at an individual level, variations in metabolism are insignificant, unlike Alzheimer’s disease, where structural (looking for atrophy) and functional brain imaging tests (hypometabolism) contribute to the diagnosis.

Depression is cured, memory functioning is restored (such as sleep, appetite, etc.), but a shortage of biographical memories collected during this period with an excess of sad memories may remain.

What about the effect of psychotropic treatments? Do they aggravate memory difficulties?

If we accept that depression modifies cognition in particular by altering the functioning of attention, slowing down the speed of information processing, and making encoding or retrieving memories more laborious, what are we to think of the effect of psychotropic treatments? Do they aggravate memory difficulties?

Depression is a serious illness and, in most cases, treatment consists of medication and psychotherapy.

The diversity of situations precludes a general answer. It is necessary to take into account the age of the patients, other mental weaknesses such as anxiety or the consumption of toxic substances: alcohol, cannabis, etc., the type of depression (reactive to a vital calvary or endogenous), and the severity.

The Recommendations of the High Authority for Health (HAS) drawn up by a college of experts (2017) indicate that supportive psychotherapy carried out even by the general practitioner is offered without recourse to medication only in case of moderate depression. An evaluation is essential at 4 or 8 weeks to review the need to introduce or not a pharmacological treatment, depending on its efficacy.

Insufficiently effective support or, of course, severe depression requires antidepressant medication, which should always be accompanied by psychotherapy and, as far as possible, the support of those around you.

The antidepressant treatment is chosen based on: 1/ the patient, 2/ the symptoms and always in the doctor-patient alliance.

These treatments, respecting the prescription rules, have few cognitive side effects and most of the time people testify to it by restoring sleep, vitality and reducing dark thoughts, observing better functioning for themselves (“ I start to be able to read again without forgetting what I just read on the previous page “).

SRIs are most often the reference therapeutic classes. Benzodiazepines are a treatment for panic-anxiety and are therefore currently prescribed only when necessary and for short periods. Long-lived benzodiazepines have a risk of many side effects, especially after the age of 65, and their use responds to rare and highly specialized indications.

The benefit/risk balance is clearly unfavorable for chronic treatments, with a series of potentially serious adverse effects and a source of hospitalization and excess mortality: falls, cognitive disorders, psychomotor and behavioral disorders, traffic accidents, loss of autonomy, apparition of tolerance and dependence, including risk of suicide according to a recent study. (HAS Report, 2012).

Some registries (but not all) have reported the possibility of an increased risk of major cognitive disorders (Alzheimer’s disease, but not only) during prolonged use, which led to a warning message from the ANSM and intensified reflection on your prescription.

COVID-19 and depression: do we already have enough perspective to know the impact of the pandemic on our brain and mental health? What are the repercussions?

The COVID-19 pandemic and the confinement situations have caused significant moral suffering in some people, with or without a history of mental frailty, with, however, great disparities, depending on age, the social group to which they belong, the habitat and the way of life, living alone
or not, the type of professional activity or the studies more or less abused and according to the
lockdown situations.

Many studies have been carried out at different times during this health crisis. Increased anxiety is one of the most consistent results with sometimes associated or late depressive symptoms.

We also observe the development of social phobia (isolation and avoidance) and reawakenings from previous traumas. It is important to follow future surveys carried out by Public Health France to estimate the lasting effects, particularly in the context of the conflict between Russia and Ukraine, which often disrupts sleep and aggravates anxiety (nuclear anxiety, Energy crisis, World War III ) .

Finally, the increase in addictions is a very worrying fact and an additional element of vulnerability to depression. The difficulty of collecting (often declarative) and interpreting these complex studies must be taken into account.

Article published on 01/13/2023 at 01:00 | read 74 times


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