Why does depression make the brain smaller?

The presence of a mental disorder produces great difficulties in the daily life of the patient. Schizophrenia, bipolarity, anxiety, depression … all generate a high level of suffering and induce cognitive and behavioral changes.

However, the effects of some of the psychopathologies are not limited to these aspects, but rather they produce great physiological and cerebral changes. In the case of depression, recent research suggests that suffering from this condition may be associated with narrowing of certain areas of the brain.

The results of this research were obtained by analyzing neuroimaging techniques applied to a large number of volunteers with and without depression. as well as by analyzing donated brain tissue.

Cause or consequence?

In many mental disorders, there are changes in the brain. These changes in the structure and functionality of the brain explain the symptomatology present in the disorders. But one fundamental consideration should be kept in mind: The fact that there is a correlation between brain changes and mental disorders does not indicate in which direction this relationship is given. In a large number of disorders, research reflects that changes in the brain cause or facilitate the onset of the disorder and its symptoms.

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 symptomatology.

In other words, in the brains of depressed people, certain measures and structural changes are observed that are not present in people 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 the degradation of brain structures.

Brain changes produced during depression

These studies indicate that the main deficiencies occur in the hippocampus, which is a very important brain structure when it comes to retaining certain memories in long-term memory. Depression is associated with a reduction in neuronal density in this part of the brain, In turn, causing deficits in memory, attention and information retention (which can also be observed in the depressive process itself). This hippocampal atrophy, according to studies, increases as depressive episodes recur and their duration is prolonged.

On the other hand, research conducted so far indicates that the brain is compressed, losing internal neural connections and not just in the hippocampus.

Other changes in the brain during depression

In addition to the neurons themselves during depression, glial cells are affected, especially in the frontal cortex. Blood flow to the brain is slightly altered, which, together with a slowdown in glucose metabolism in the prefrontal cortex, causes it to reduce the supply of oxygen and nutrients, also producing a long-term reduction in this. zoned. Likewise, the cerebellar amygdala also becomes smaller.

Finally, as with other disorders such as schizophrenia, the lateral ventricles dilate, occupying the space left by neuronal loss.

Reasons for Cerebral Reduction of Depression

The reason for this reduction in the brain is due to the activation of a transcription factor called GATA1 which it prevents the expression of a series of genes essential for the creation of synaptic connections. This transcription factor disrupts cognitive functions and emotions.

In addition, other data reflect that recurrent depressive states, along with stress, cause hypercortisolemia, which, if maintained, produces neurotoxicity that ultimately affects hippocampal neurons, reducing their number and interconnection. . With that, the hippocampus is reduced and its functions are affected. For this reason, it is essential to treat depressive states early, especially in cases of depression in adolescents, as the brain is not yet fully developed.

In the long term, this reduction in the brain leads to a decrease in processing speed and the ability to organize and work with information from the environment, making it difficult to find an adaptive response to situations. Likewise, depressive symptoms worsen, both due to the direct effect of reduced capacity and due to knowledge of decreased capacity.

Reasons for hope: the alterations are partly reversible

However, the fact that research has reflected this phenomenon does not imply that depressed people have a permanent deterioration, which may motivate treatment (both psychological and pharmacological) and improvement in depressive symptoms, neurogenesis and neuronal strengthening. Thus, the treatment of depression can motivate the creation of new neurons, regaining functionality lost during depressive disorder.

At the clinical level, the alterations discovered may help clarify the reason for the delay between the initiation of antidepressant use and its therapeutic effects, requiring slow changes not only in neurotransmitter availability but also at the structural level. This research may help to develop new antidepressant drugs, which could be dedicated to inhibiting factor GATA1, as well as encourage seeking professional help before the problem gets better.

Bibliographical references:

  • Kang, HJ; Voleti, B .; Hajszan, T .; Rajkowska, G .; Stockmeier, California; Licznerski, P .; Lepack, A .; Magic, MS; Jeong, LS; Banasr, M .; Fils, H. and Duman, RS (2012). Decreased expression of genes linked to synapses and loss of synapses in major depressive disorders. Nat. Med; 18 (9): 1413-7.
  • Miguel-Hidalgo, JJ and Rajkowska, G. (2002). The morphological brain changes depression. Can antidepressants reverse them ?. Ibero-American Society for Scientific Information.

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