Why does depression make the brain smaller?

The presence of a mental disorder It causes great difficulty in the daily life of those who suffer from it. Schizophrenia, bipolarity, anxiety, depression... all of them generate a high level of suffering and induce changes at the cognitive and behavioral level.

However, the effects of some of the psychopathologies are not limited to these aspects, but rather produce great physiological and cerebral changes. 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 these investigations have been 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, changes occur at the brain level. These changes in brain structure and functionality explain the symptoms present in the disorders. But it is necessary to take into account a fundamental consideration: the fact that there is a correlation between brain modifications and mental disorders does not indicate in which direction it occurs said relationship. In a large number of disorders, research shows that

brain alterations cause or facilitate the appearance of the disorder and its symptoms.

In the case of depression, however, the latest research indicates that the reductions observed are produced after the appearance of symptoms, being an effect derived from the persistence of the symptomatology.

That is to say, in the brain of depressed people some measures and modifications of the structure 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 an intervention early, in order to avoid not only the persistence of symptoms but also the degradation of structures cerebral.

Brain changes produced during depression

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

On the other hand, the investigations carried out so far indicate that the brain is compressed, losing internal neural connections and not only in the hippocampus.

Other brain changes 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 slowdown in the metabolism of glucose in the prefrontal cortex They cause it to see reduced oxygen and nutrient supply, producing a long-term reduction in this area as well. In the same way, the cerebellar tonsil also gets smaller.

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

Reasons for brain reduction in depression

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

Likewise, other data reflect that recurrent depressive states, as well as stress, cause hypercortisolemia, which if continues to produce neurotoxicity that ends up affecting hippocampal neurons, reducing their number and their interconnection. With that, the hippocampus is reduced, its functions also being 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 shrinking of the brain causes a drop in processing speed and in the ability to organize and work with information obtained from the environment, which makes it difficult to find an adaptive response to situations vital. Similarly, depressive symptoms are worsened, both due to the direct effect of decreased ability and due to knowledge of decreased ability.

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, and may motivate treatment (both psychologically and pharmacologically) and improve depressive symptoms neurogenesis and strengthening neural. Thus, treating depression can motivate the creation of new neurons, recovering the functionality lost during the course of the depressive disorder.

At a clinical level, the alterations discovered can help to clarify the reason for the delay between the start of consumption of antidepressants and its therapeutic effects, requiring slow changes not only in the availability of neurotransmitters but also at a structural level. This research may contribute to the development of new antidepressant drugs, which could be used to inhibit the GATA1 factor, as well as encourage the search for professional help before the problem becomes consolidate.

Bibliographic references:

• Kang, H.J.; Voletti, B.; Hajszan, T.; Rajkowska, G.; Stockmeier, C.A.; Licznerski, P.; Lepack, A.; Majik, M.S.; Jeong, L.S.; Banasr, M.; are, 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 of Scientific Information.