Why does depression make the brain smaller?
A strange effect that has been demonstrated by encephalic scan tests.
The presence of a mental disorder causes great difficulty in the daily life of the sufferer. Schizophrenia, bipolar disorder, anxiety, depression... all of them generate a high level of suffering and induce cognitive and behavioral modifications.
However, the effects of some of the psychopathologies are not limited to these aspects, but also produce great modifications at the physiological level. produce great modifications at the physiological and cerebral level.. In the case of depression, recent research suggests that suffering from this pathology could be associated with a shrinkage of some brain areas.
The results of this research have been obtained through the analysis of neuroimaging techniques applied to a large number of volunteers with and without depression. as well as by analysis of donated brain tissue.
Cause or consequence?
In many mental disorders, changes occur at the brain level. These changes in brain structure and functionality explain the symptomatology present in the disorders. But a fundamental consideration must be taken into account: the fact that there is a correlation between brain modifications and mental disorders does not indicate in which direction this relationship exists. In a large number of disorders, research shows that brain alterations cause or facilitate the onset of the disorder and its symptomatology..
In the case of depression, however, the latest research indicates that the observed reductions occur after the onset of symptomatology, being an effect derived from the persistence of the symptomatology.
In other words, in the brains of depressed persons, measures and structural modifications are observed that are not present in subjects without this disorder. For this reason, the research carried out reinforces the idea of the importance of early intervention, in order to avoid not only the persistence of symptoms but also the degradation of brain structures.
Brain modifications produced during depression
These studies indicate that the main affectations occur in the hippocampus, which is a very important brain structure for the storage of certain memories in the long-term memory. Depression is associated with a reduction in the neuronal density of this part of the brain, causing deficits in the hippocampus.This in turn causes deficits in memory, attention and retention of information (which can also be observed in the depressive process itself). This hippocampal atrophy, according to the studies, increases as the depressive episodes are repeated and as their duration is prolonged.
On the other hand, research carried out to date indicates that the brain is compressed, losing internal neuronal connections and not only in the hippocampus.
Other changes in the brain during depression
In addition to the neurons themselves, glial cells are affected during depression, especially in the frontal cortex. The blood supply to the brain is slightly altered, which, together with a slowing of glucose metabolism in the prefrontal cortex, leads to a reduction in the supply of oxygen and nutrients, resulting in a long-term reduction of this area as well. Similarly, the cerebellar amygdala also shrinks.
Finally, as in other disorders such as schizophrenia, the lateral ventricles undergo dilatation, occupying the space left by neuronal loss..
Reasons for brain shrinkage in depression
The reason for this brain shrinkage is due to the activation of a transcription factor known as GATA1, which prevents the expression of a number of genes essential for the creation of synaptic connections. prevents the expression of a series of genes essential for the creation of synaptic connections.. This transcription factor interrupts cognitive functions and emotions.
Likewise, other data reflect that recurrent depressive states, as well as stress, cause hypercortisolemia, which if maintained produces a neurotoxicity that ends up affecting the neurons of the hippocampus, reducing their number and interconnection. Thus, the hippocampus is reduced, the hippocampus is reduced and its functions are also affected.. For this reason it is essential to treat depressive states early, especially in the case of depression in adolescents, whose brain is not yet fully developed.
In the long run, this reduction of the brain causes a decrease in processing speed and in the ability to organize and work with the information obtained from the environment, making it difficult to find an adaptive response to life situations. Similarly, depressive symptoms are worsened, both due to the direct effect of the reduction in capacities and due to the knowledge of the decrease in ability.
Reasons for hope: the impairments are partly reversible.
However, the fact that research has reflected this phenomenon does not imply that depressed people have a permanent deterioration, since treatment (both psychological and pharmacological) and the improvement of depressive symptoms can be motivated by neurogenesis and neuronal strengthening. Thus, treating depression can motivate the creation of new neurons, recovering the functionality lost during the course of the depressive disorder.
At the clinical level, the alterations discovered may contribute to clarify the reason for the delay between the onset of Antidepressant use and its therapeutic effects, requiring slow changes not only in the availability of neurotransmitters but also at the structural level. This research may contribute to the development of new antidepressant drugs, which could be dedicated to inhibit the GATA1 factor, as well as favoring the search for professional help before the problem consolidates.
Bibliographic references:
- Kang, H.J.; Voleti, B.; Hajszan, T.; Rajkowska, G.; Stockmeier, C.A.; Licznerski, P.; Lepack, A.; Majik, M.S.; Jeong, L.S.; Banasr, M.; Son, H. & Duman, R.S. (2012). Decreased expression of synapse-related genes and loss of synapses in major depressive disorder. Nat. Med; 18 (9): 1413-7.
- Miguel-Hidalgo, J.J. & Rajkowska, G. (2002). Morphological Brain Changes Depression. Can Antidepressants Reverse Them?. Iberoamerican Society for Scientific Information.
(Updated at Apr 14 / 2024)