March 2, 2024

What is Depression, and what are its causes and symptoms?

Depression is defined as a set of predominantly affective symptoms (pathological sadness, apathy, anhedonia, hopelessness, decay, irritability, subjective feeling of malaise and impotence in the face of the demands of life), although, to a greater or lesser degree, they are also Cognitive, volitional and somatic symptoms are present, so it can be said that there is a global psychic and physical affectation, with special emphasis on the affective sphere, according to the Clinical Practice Guideline on the Management of Depression in Adults, of the Ministry of Health, Social Services and Equality.

Depression “is the fourth leading cause of illness and disability among adolescents between the ages of 15 and 19 and the fifteenth among those between the ages of 10 and 14.

“There are certain people who, because of their nature, are more likely to suffer from depression,” according to Ángeles Sánchez-Cabezudo, a psychiatrist at the Toledo Hospital Complex.

“Responsible people, with low self-esteem, demanding, perfectionists, with a high sense of duty and respect, meticulous, low tolerance for failure and with very rigid life approaches have a higher risk of suffering from depression,” he explains. In addition, “they attach great importance to control, so they like to know what is happening at all times. They love routine, hate improvisation or surprises and suffer if they feel they do not control some aspect of their lives”.

Depression can begin at any age, although its highest prevalence occurs between 15 and 45. The symptomatology of the disorder can be different with age: young people show fundamentally behavioural symptoms, while older adults have more frequent somatic symptoms. 


The reasons for depression are varied, but a person’s biochemistry can help explain some causes. For example, suffering people show very high levels of cortisol (a hormone ) and various chemicals that target the brain, such as dopamine, serotonin and norepinephrine. These levels may be increased for genetic reasons. The family origin of depression is explained by children receiving a sad view of the world due to their parent’s behaviour or growing up in an environment that is not fed.

Despite depression not being caused by family, deep emotional losses can cause biochemical changes that promote depression. These changes can cause the disease not immediately but later.

Other factors may be the loss of a job or the lack of adaptability to certain changes. For example, although it is not known exactly what causes depression, several factors are identified as imbalances of neurotransmitters in the brain. 

As stated in the Clinical Practice Guideline on the Management of Depression in Adults, depression is a multifactorial and complex process whose probability of development depends on a wide group of risk factors, without it has been possible to establish so far. their totality nor the multiple interactions between them. 

  • The prevalence and occurrence of depressive disorders are higher in women than in men, beginning in adolescence and continuing into adulthood.
  •  Chronic physical and mental diseases and the possible association with alcohol and tobacco consumption are also important risk factors.
  •  It has been observed that patients, mainly men with a history of panic attacks, have a higher risk of developing major depression.
  • An association between migraine and depression has been described so that patients with major depression had a higher risk of suffering from migraine, and, in turn, those who had migraine (not another type of headache) had a higher risk of major depression.
  • One of the most frequent approaches in investigating the genes involved in the development of depression is the analysis of the role of monoamines. Among all the genetic variants studied, one factor that could influence its development is the presence of a polymorphism in the gene that encodes the serotonin transporter, which would decrease the transport of this neurotransmitter.
  • The presence of heart disease and various endocrine pathologies, such as diabetes, hypo- or hyperthyroidism, Cushing’s syndrome, Addison’s disease, and hyperprolactinemic amenorrhea, seem to increase the risk of depression.
  • First-degree relatives of patients with major depressive disorder have twice the chance of presenting depression than the general population, which is also important in second-degree relatives.


Typically, “depression is characterised by prolonged periods of more than two weeks of low mood and apathy, but it presents a wide variety of symptoms that Sánchez-Cabezudo describes:

  • Affective: sadness, irritability, inability to enjoy, suicidal thoughts, hopelessness, anxiety or guilt.
  •  Cognitive: indecision, loss of concentration or forgetfulness.
  • Somatic: fatigue, changes in appetite or weight, insomnia, hypersomnia, sexual dysfunction, headache, stomach problems, chest pain, agitation

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