Distress Theory Of Depression: What It Is, And How It Explains This Disorder
In Spain, more than 2.4 million people suffer from depression in their daily lives, this means that more than 5.2% of the Spanish population lives with a feeling of anguish and acute sadness that interferes or makes it impossible to live their lives. normally.
Despite the high incidence of this disorder or emotional condition, there are still great disagreements within the scientific community regarding its true cause. One of these theories is the distress theory of depression which we explain throughout this article.
Also known as the inflammatory theory of depression, this explanatory model of endogenous depressive disorders created by UK physician and researcher Bruce G. Charlton In 2000, he tried to explain the origin of depression from a physical or organic point of view and not as a psychological reaction.
This theory begins with the idea that when our body falls victim to some type of infection, our own body emits an inflammation response through which a series of hemodynamic alterations, lymphatic levels and the release of a series of agents such as cytokines, histamine neuropeptides, etc. are carried out, with the aim of restoring the health of our body.
Furthermore, along with inflammation a psychological phenomenon known as illness behavior appears This type of psychological response is characterized because the person experiences a series of sensations of fatigue, drowsiness, anhedonia and cognitive alterations. All of these symptoms coincide with part of the clinical picture of major depression.
The origin of this disease behavior would be found in the effects that certain proteins, specifically cytokines, whose levels increase when a virus or infection appears, cause in our brain.
This association between the physical or organic response of inflammation and the psychological response is what the discomfort theory suggests. According to this, endogenous depression is a pathological variety of illness behavior. Because of which the symptoms remain over time. Therefore, according to this theory, depression is caused by the effects of chronic, low-level organic inflation and by chronic activation of the immune system.
Finally, Charlton himself proposes that the true effect of antidepressant drugs in alleviating the symptoms of the disease is found in the analgesic effect that most of these possess, so by reducing organic inflammation, the symptoms of depression also decrease.
What evidence is this explanation based on?
Although at first it may be somewhat difficult to believe that depression is not caused by an external factor that provokes this response, the theory of discomfort is based on a series of empirical evidence that supports it.
1. Symptom coincidence
As mentioned above, the symptoms of major depression coincide in many ways with those of illness behavior, which tends to appear when we suffer from some type of physical illness.
In these cases symptoms such as fatigue, decreased physical energy, or feelings of distress and sadness They appear with the aim of keeping our body at rest and recovering as soon as possible.
2. The effect of cytokines
One of the physiological responses that our body provokes when faced with the threat of a disease is the increase in cytokines This protein causes inflammation with the intention of transmitting to our body that it is in a state of alert or threat.
If we take into account that, usually, in disorders with depressive symptoms the levels of cytokines are much higher than usual, we can hypothesize a kind of relationship between these two factors.
Furthermore, in the specific case of bipolar disorder, cytokine levels decrease during episodes of mania or remission of depressive symptoms so this reinforces this association.
3. Action of antidepressants
Antidepressant drugs have an effect on cytokine levels, specifically they decrease them. Therefore, this reinforces the idea that the main cause of endogenous depression is found in the effects that these proteins cause in the body.
4. The inflammatory response system and depression
Some studies have shown that laboratory inoculation of inflammatory substances or agents, causes a series of symptoms typical of clinical symptoms of depression and anxiety
Furthermore, a clear relationship has been established between the activation of our body’s inflammatory response system and depression; since this is continuously activated during this disorder.
The inflammatory response system works through the activation of the hypothalamic-pituitary-adrenal axis, which affects the regulation of certain neurotransmitters such as serotonin and catecholamines, directly related to states of depression.
5. Antidepressant action of anti-inflammatory drugs
Finally, some research has discovered that the administration of anti-inflammatory medication in some cases of endogenous depression not only significantly improves its symptoms, but also does so to a greater extent than some antidepressants.
What if there is depression but no inflammatory disease?
The main criticism of the explanatory model of distress theory in depression is that There are a large number of cases in which a physical cause could not be found or sign of organic inflammation in the patient.
However, according to this theory, it is argued that psychological stress processes can cause this inflammation just as any type of infection does, thus causing symptoms of depression.
Experiencing high levels of stress over a long period of time has been linked to increased levels of proinflammatory cytokines. Which, as we have already explained previously, have a direct effect on the levels of serotonin and other neurotransmitters related to depression.
