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Circadian dysrhythmia as a pathogenesis of endogenous depression

Circadian dysrhythmia as a pathogenesis of endogenous depression

The explanation of the symptoms of endogenous depression Only in cognitive terms does it seem difficult (e.g., seasonal differences in incidence, rapid affective changes, mood swings during the day, etc.).

Some type of biological mechanism or abnormality It seems necessary to adequately explain these symptoms. In this sense, it has been hypothesized that the alteration in circadian rhythms could constitute the pathogenesis of endogenous depression.


  • 1 Definition of pathogenesis and its relationship with endogenous depression
  • 2 Why are certain forms of depression resistant to treatment?
  • 3 Circadian dysrhythmia as a pathogenesis of endogenous depression: Conclusions

Definition of pathogenesis and its relationship with endogenous depression

The pathogenesis of a disease refers to those factors that give the disease its temporal and spatial autonomy. As, for example, some biological alteration triggered by the etiologic agent, and that lasts after it disappears.

In this way, they could distinguish three concepts within the notion of disease:

  • The cause or etiology
  • Aspects of genetic vulnerability, constitutional or psychological
  • The pathogenesis or physiological alteration caused by the etiology

For example, in the case of an ulcer, one aspect of the etiology may be stress, vulnerability, the greater gastrointestinal reactivity. The pathogenesis of the ulcer, the stomach injury.

This last aspect makes the ulcer persist although the stressors are removed, which makes the ulcer something more (a disease) than a reaction to external situations (such as gastritis that disappears when the aversive situation is removed).

In this way, The concept of pathogenesis is useful to differentiate reactive phenomena and disease.

Why are certain forms of depression resistant to treatment?

The pathogenesis can explain why depressive state is maintained in situations that are no longer stressful., neurobiological and hormonal symptoms, the great latency of the effects of antidepressants, etc.

The dysfunction of circadian rhythms would constitute the organic "injury" in depression which, caused by psychological agents (although possibly facilitated by various vulnerability factors), in turn causes emotional and cognitive alterations that cause the disorder to persist.

The concept of pathogenesis allows us differentiate depressive reactions from endogenous depression, which presents neurobiological dysfunction characteristics. In which, therefore, it seems necessary to postulate certain somatic disorders or physiological mechanisms involved in its manifestation.

The "rupture" of homeostasis of circadian rhythms

Disruption of circadian rhythms provides autonomy to depression, leaving to be merely a reactive phenomenon. Once altered, circadian rhythms need some time to be restored.

Depressive reactions to external events can be expected to resolve once the stressor is removed. Nevertheless, in endogenous depression the alterations last after the stressor is removed. Nor do they respond acutely to medication.

At present It is a clear fact that psychological stress is a precursor of both endogenous and reactive depression. However, vital events do not usually trigger endogenous depression immediately.

In fact, a relatively long period of time may elapse before the episode appears. This is difficult to explain, since sometimes depression occurs when crises have resolved.

A theoretical model can be proposed, based on the alteration of circadian rhythms as pathogenesis of endogenous depression.

Model on the mechanisms by which psychosocial stress triggers endogenous depression

First phase

As a first step, vital events cause circadian dysrhythmia through two mechanisms:

  • Directly through the physiological responses related to stress
  • Indirectly through the alteration of daily routines

Second phase of the triggering model of endogenous depression

Secondly it is a known fact that circadian dysrhythmia carries consequences at the neurovegetative and neuropsychological level. Therefore, it causes a physiological weakness similar to that of endogenous depression and learned helplessness

For example, symptoms of dysphoria, weight loss, anorexia, lack of energy, insomnia and irritability. The alteration of circadian rhythms leads to motivational deficits.

The presence of a functional state characterized by poor attention, loss of energy and interest and ruminant thoughts is typical. As is known, one of the hallmarks of depression.

You also have to take into account the effort required to overcome stressful life events and the cost of that effort. The cost per unit of effort varies according to the energy level of the person.

Thus, the effort required to overcome a problem may be medium, but the behavior may not start because the energy level You can see that effort as very high.

Third phase

As a third step, circadian dysrhythmia acts by reducing the sense of self-efficacy, stimulating the implementation of maladaptive attributions.

Dysrhythmia (e.g., sleep disturbance, appetite, sexuality, slowing of motor functions, emergence of negative thoughts and memories, etc.) introduces an aspect of non-contingency in areas of intimate personal functioning, precipitating a state of unpredictability and confusion in personal functioning.

Likewise, it alters processes that previously occurred automatically, so it constitutes an aversive stimulus (eg, failure in sexual functioning, concentration, sleep, appetite, etc.).

Helplessness appears in the third phase

This status stimulates a feeling of helplessness and loss of self-esteem based on an evaluation of current performance compared to past performance.

In the same way, the sense of mastery and self-efficacy usually entails the proper management of daily routines. Failure to control these routines is an important source of discomfort.

Thus, can make everyday social and environmental interactions unpleasant. An important difference between reactive depression and endogenous depression is that in the first one there is a close relationship between mood and identifiable stressors, something that does not occur in the second.

In endogenous depression the disorder can be seen as unexplained, where it is difficult to relate the mood to a premorbid situation. It gives the impression of the absence of precipitating factors, or that there is no relationship between their severity and the severity of depression.

The loss of energy and interest associated with the circadian alteration can encourage dysfunctional and demoralizing thoughts, triggered by the lack of energy to carry out normal tasks.

Third phase: the uncertain origin of endogenous depression

The origin of these alterations is dark for the one who suffers them and for the close people. Therefore, the judgment of what they represent is made under more uncertainty and this makes it the cognitive biases characteristic of depression are more likely to be mobilized (e.g. internal, stable and global attributions).

In turn, the implementation of these cognitive biases favors a greater decrease in feelings of self-esteem and self-efficacy, producing an interaction as a vicious circle between both elements.

Thus, depression could begin as a disorder of moderate intensity, and later develop in a more severe and chronic form with the implementation of cognitive distortions.

A primary factor in this whole process is the negative interpretation of the internal state itself, so that when people are able to attribute emotional disturbances to specific factors, subsequent problems are less widespread (eg, long plane trips, changes in work schedules, etc.).

Third phase: a dark origin often involves autoinculpations

In the absence of a clearly understandable external cause, problems arising from dysrhythmia are more likely to be attributed to personal dispositions. Thus, The cognitive reaction, rather than the circadian pathology, may be the one that determines the chronicity and severity of the depressive disorder.

Depressed humor differentially activates global self-devaluing concepts in subjects who have previously suffered from depression. These cognitive processes work by way of dysfunctional attitudes that can transform a moderate and transient episode of depression into a more persistent and severe one.

Fourth phase: the irremissible fall in depression

By last, the implementation of the previous cognitive biases leads to a state of demoralization and finally to depression. It is the operation of cognitive biases that transforms the state of dysphoria into a state of depression.

Due to the operation of these same biases, it could also be expected that demoralization persists some time after the primary alterations have disappeared.

In this sense, it is a common clinical fact that the response to facet antidepressants such as sleep and appetite occurs at 2 or 3 weeks of treatment, while alterations in self-esteem and self-confidence take longer to improve.

Circadian dysrhythmia as a pathogenesis of endogenous depression: Conclusions

In conclusion, Addressing endogenous depression continues to pose a challenge to mental health professionals. To know more about the origin and treatment of depression, as well as to propose methods and techniques for its approach from a specific perspective is something that is still to be done.

Therefore, more research on this subject is required, which, although somewhat more infrequent than reactive depression, is no less important.

The problem is that researchers and health workers generally take their efforts to study the general variables of all mood problems. We are absorbed in analyzing thousands of data to try to homogenize the cases.

It is the patients, with their individuality and personal idiosyncrasy, that must adapt to the norm. The ideographic is set aside for the study of the nomothetic. In short, the tree does not let us see the forest.


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Baztán, Á. A. (2016). Anthropology of depression.Subjectivities Magazine8(3), 563-601.

Carrillo-Mora, P., Barajas-Martínez, K. G., Sánchez-Vázquez, I., & Rangel-Caballero, M. F. (2018). Sleep disorders: what are they and what are their consequences?Journal of the Faculty of Medicine (Mexico)61(1), 6-20.

Gatón Moreno, M. A., González Torres, M. Á., & Gaviria, M. (2015). Seasonal affective disorders, "winter blues".Journal of the Spanish Association of Neuropsychiatry35(126), 367-380.

Portellano Ortiz, C. (2019). Depression, cognitive decline and quality of life in aging with the SHARE project (Survey of Health, Ageing and Retirement in Europe).

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