Major Depression: What Causes It And How Is It Treated?

Major depression is one of the most serious and debilitating psychological disorders.  It is a pathological state that goes beyond a simple state of sadness. It involves despondency, suicidal thoughts, physical and psychological exhaustion, and low self-esteem.

Thus, one thing that experts tell us is that this condition transcends even simple emotional pain. Thus, if there is something that characterizes it, it is also physical painStudies such as those carried out by doctors Goesling, J.Clauw, and Hassett, A.L. of the University of Michigan, for example, show us this correlation with the brain’s pain centers.

With all this, we can certainly intuit the impact that major depression can have on people. We are faced with a reality of multifactorial origin that requires adequate treatments to deal with it. We need specialized professionals for a disorder with both biological and psychological origins.

What is major depression?

As we have said,  major depression is a step beyond sadness. It is classified as a disorder and therefore we must treat it with the seriousness and respect that this implies. Before explaining its possible causes, let’s define what the disorder consists of.

  • Major depression is defined by the simultaneous presence of a series of important symptoms, lasting for two weeks.
  • For diagnosis, at least one of these symptoms must be either a sad, depressed mood or a loss of pleasure ( anhedonia ) from activities that you used to enjoy.

However, these symptoms alone are not enough, it is also required that these symptoms entail a marked interference with the daily life of the person suffering from them.

  • On the other hand, the diagnosis of major depression requires meeting two additional exclusion criteria: that the symptoms are not caused by an illness or the ingestion of any substance.
  • On the other hand, the symptoms may not be due to a normal grief reaction to the death of a loved one.
  • There is a subtype, called melancholic, in which a series of symptoms occur, such as a very marked loss of pleasure, lack of emotional activation, or psychomotor inhibition.
  • In addition, to be diagnosed with major depressive disorder, the person must not have had any episodes of mania or hypomania or it must have been a case of schizophrenia or another psychotic disorder.

Symptoms of major depression

    • Constant discouragement.
    • Loss of interest.
    • Weight gain or loss.
    • Lack of concentration.
    • Insomnia or hypersomnia
    • Feelings of guilt
    • Suicidal ideation
    • Low self-esteem.
    • Exhaustion
    • Physical pain.

What causes major depression?

There is no single cause that determines whether a person develops major depressive disorder. We are dealing with a multifactorial condition where several causes converge.

Biological causes

At a biological level, chemical imbalances in the brain, especially of the already-known neurotransmitter serotonin, would be responsible for the person entering this state of marked sadness and anhedonia.

Today we do not know for certain whether these biochemical imbalances are a cause or consequence of depression, so we cannot conclude that low levels of serotonin in the brain are responsible for a person becoming depressed.

On the other hand, there are more psychological theories: currently the most supported.  The best-known theory is that of  Aaron Beck. Its popularity rests on two facts:

  • It is a theory that fully embraces the theoretical assumptions and methodology of information processing.
  • Second, it has given rise to a type of treatment—cognitive therapy—that is as effective or more effective than drug therapy, with the added benefit of further reducing the risk of relapse and side effects.

Psychological causes: what does Beck’s theory tell us about depression?

For Beck,  after the loss of the reinforcer (a positive consequence of the behavior) and the subsequent natural emotion of sadness, a series of cognitive errors would appear in the person:  failures in processing information from the outside, which would be responsible for the appearance of the disorder and its continuation over time.

  • Let’s say that the depressed person is not able to be objective when perceiving the information around him and therefore negatively distorts reality.
  • Some of the most common distortions seen in depressed people are, for example, the magnification of negative events that occur in their lives or the minimization of positive events that take place. 

In this way, the person becomes immersed in the so-called negative cognitive triad, which is nothing more than having a permanent negative vision of oneself, of one’s own experience and, what is worse, of the future.

What treatments are there for major depression?

Broadly speaking, we can establish a clear difference between pharmacological treatments and psychological treatments.

Pharmacological treatments

  • Within pharmacological treatment, the most commonly used drugs are those called  Selective Serotonin Reuptake Inhibitors (SSRIs).
  • They are used more frequently because they have fewer side effects than tricyclic antidepressants or monoamine oxidase inhibitors (MAOIs). We are all familiar with Prozac (fluoxetine), which falls into this group.
  • The aim of these drugs, as their name indicates, is to prevent serotonin from being reabsorbed quickly and, therefore, to prevent its effect on the brain from being lost so quickly when it is released into the small space that exists between neurons.

The drug would act as a first impulse that would make the patient feel more encouraged to take action.

Can depression be cured with medication? No. As we have said, medication helps people who are unable to take that first step to feel more emotionally prepared to do so, and it is precisely this first step that will help their depression improve.

Psychological treatments

On the other hand,  within psychological treatments, those that have proven most effective are those that are integrated within the cognitive-behavioral current.

  • Based on the fact that the cause of depression is that the patient has a distorted perception, towards the negative pole, of his reality and that based on this, he feels and acts, the objective of this treatment will be for the person to modify these cognitive biases.
  • Following this logic, therapy is focused on modifying the patient’s way of thinking, providing tools to identify and modify these biases.
  • Thus, thanks to a change in their way of thinking, the patient will begin to carry out the activities that they have been putting aside and that previously gave them pleasure, as well as to incorporate new ones that can benefit and please them.

Behavior modification

In this sense, we do not have to start by modifying the patient’s thoughts and beliefs, but we can start directly with behavioral activation. If this option is chosen, we will help the patient to design a daily schedule in which different tasks will be included that the patient commits to completing.

What is the goal? That the person who has lost, due to his lack of activity, the vital reinforcements that he used to have and that made him happier, recovers them through action.

The weekly plan should include both mastery and pleasure tasks. Mastery tasks are those that will help the patient feel competent and not see himself as a failure or useless.

  • An example might be resuming or starting English classes. Pleasure tasks are those that involve leisure and pleasure, such as shopping, taking a walk, calling a friend, etc.
  • What usually happens is that the depressed person will tell us that he or she does not feel motivated to do any task, that he or she does not find any meaning in it, that he or she does not believe that this is his or her problem or that he or she has no energy or desire.

Typically, the person has a drawer full of excuses for not fulfilling these tasks. As therapists, we must know that this attitude and these excuses are part of the disorder and make the person see that he or she must fight against this inertia.

Modifying cognitions

The cognitive techniques that we will use to modify negative thoughts and beliefs will be cognitive restructuring and behavioral experiments.

  • Through restructuring, we aim to get the person to change their negative way of thinking for a more adapted vision of reality – not a positive one – and to realize that they are capable of enduring it and that it is not as terrible as they think.
  • On the other hand, behavioral experiments will help the patient realize how distorted some of his thoughts are. 
  • The therapist will suggest that the patient carry out an activity or action. The patient must write down what he or she thinks will happen and once the activity or action has been carried out, in the next session, the therapist and patient will analyze what happened.

Finally, and depending on the patient,  we can use other more emotional techniques, such as rational emotive imagination or mindfulness.

To conclude, one thing we must be clear about is that there is no single treatment for major depression. We certainly have multiple strategies at our disposal.


All sources cited were thoroughly reviewed by our team to ensure their quality, reliability, timeliness, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.


  • Rittberg, B. R. (2016). Major depressive disorder. In  The Medical Basis of Psychiatry: Fourth Edition (pp. 79–90). Springer New York. https://doi.org/10.1007/978-1-4939-2528-5_5
  • Flint, J., & Kendler, K.S. (2014, February 5). The genetics of major depression.  Neuron.  https://doi.org/10.1016/j.neuron.2014.01.027
  • Goesling, J., Clauw, D.J., & Hassett, A.L. (2013). Pain and depression: an integrative review of neurobiological and psychological factors.  Current Psychiatry Reports, 15, 421-428
  • Ortiz-Tallo, M (2004).  Psychological disorders.  Aljibe Editions.
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2024-09-30