Depressive disorder: what are the causes and symptoms of depressed mood?

Depressive disorder: what are the causes and symptoms of depressed mood?
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Depression is a serious disorder that affects approximately one in ten people in the world.

Most common symptoms

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Depression is a serious illness that affects approximately one in ten people in the world.

Although there are many effective medications and psychotherapy options, most patients with depression go undiagnosed and untreated.

Depression is still stigmatised as a mental illness and most people are ashamed to seek professional help. Therefore, its diagnosis is often delayed.

A feared consequence of depression left untreated in this way is the risk of suicide. Up to 15% of patients with depression choose to end their lives in this way.

How is it characterised?

Depression is a serious and increasingly common mental illness. In psychiatry it is classified as an affective disorder.

An affective disorder means that it is based on a pathologically altered mood.

Depression is a major medical, but also social and economic problem.

Among mental illnesses, depression is the most common.

Alarmingly, up to 10-15% of the world's population will experience some form of depressive episode at least once in their lifetime. Another serious aspect of depressive disorder is its recurrence and frequent chronic course.

The most serious consequence of untreated depressive disorder is the risk of suicide.

Critical concomitants of depression are the worsening or development of serious somatic illnesses, such as cardiovascular, gastroenterological or neurological diseases.

Depression is also characterised by absenteeism, i.e. absence from work. The phenomenon of presenteeism also occurs. The depressed person is present at work, but their productivity is reduced to a minimum.

This phenomenon is related to the negative economic consequences of the illness.

The economic consequences of depression can be expressed in terms of DALYs (Disability Adjusted Life Years). From 1990 to 2016, the number of DALYs increased by up to 50% worldwide.

This puts depression in the top ten diseases that place a significant economic burden on society.

Many patients remain unaided. Their illness is often not recognised and therefore not treated.

Depression is still stigmatised as a mental disorder.

Almost 60% of people with depression do not even seek medical help for fear of unacceptable opinions from others, feelings of shame and failure in their personal and professional lives.


The cause of depressive disorder has not yet been clearly elucidated. Currently, a multifactorial mechanism of its onset is assumed. Genetic and environmental factors play an important role.

Some scientific studies suggest that genetic factors do not have a major influence on the development of late-onset depression. In the development of early-onset depression, genetics appears to be one of the key causes.

First-degree relatives (mother, father) are up to three times more likely to develop depression than the general population.

Depression develops even in people who have no family history of depression. This fact points to the substantial influence of environmental factors on the development of this illness.

The main triggers of depression include traumatic life events and difficulties.

Traumatic experiences, such as the death or loss of a loved one, lack of social support, caring for a seriously ill or disabled person, financial problems or interpersonal conflicts, are huge stressors for some individuals that can trigger depression.

When emotionally stressed, people with the following character traits are prone to developing depression:

  • orderliness
  • conscientiousness
  • caring
  • focus on performance
  • dependence on intimate personal relationships
  • obsession
  • restraint
  • discretion
  • dominance

So-called potential biological risk factors are chronic illnesses, which are often accompanied by deep and chronic depression.

Examples are:

Dysregulation and the interaction between neurotransmitter availability, receptors and sensitivity are likely to play a role in the development of depression.

The most important neurotransmitter in the pathogenesis of depression is serotonin and the disruption of its activity in the central nervous system.

Other neurotransmitters responsible for the development of affective disorders are:

  • noradrenaline
  • dopamine
  • glutamate
  • the neurotrophic factor BDNF

Seasonal affective disorder is a form of depression that appears in the fall and winter. It disappears in the spring and summer. This type of depression is also caused by changes in CNS serotonin levels, but these fluctuations are due to changes in circadian rhythms and reduced exposure to sunlight.

Not to be overlooked is the risk of taking many medications or increased amounts of alcohol. Medications that can trigger a depressive disorder include:

  • acyclovir
  • amphetamine derivatives
  • anabolic steroids
  • anticonvulsants
  • baclofen (after rapid discontinuation)
  • barbiturates
  • benzodiazepines (after withdrawal)
  • beta-blockers
  • clonidine
  • oral contraceptives
  • corticosteroids
  • digitalis
  • interferon alfa
  • isoniazid
  • levodopa
  • metoclopramide
  • non-steroidal antirheumatic drugs
  • theophyllines
  • thiazides
  • thyroid hormones


A characteristic symptom of all affective disorders is a pathologically altered mood.

In the case of depressive disorder, it is primarily pathological sadness. The patient may not only feel sadness. He may also feel empty, disinterested, depressed, anxious and sometimes sullen and nervous.

Such a sad mood differs from normal, commonly felt sadness in its unreasonable intensity without any apparent stimulus and also in its long duration.

Depressive episodes are divided into four forms according to the severity of symptoms:

  1. mild depressive episode
  2. moderate depressive episode
  3. severe depressive episode without psychotic symptoms
  4. severe depressive episode with psychotic symptoms

Pathological depressed mood is also associated with other symptoms:

  • Anhedonia - Inability to enjoy activities that previously brought pleasure and pleasant feelings to the individual.
  • Daily mood swings - Typically, the patient feels worst in the morning, experiencing so-called morning pessimism, unable to start the day, and in extreme cases unable to even get out of bed (stupor).
  • Eating and appetite disturbances - More often a decrease in appetite, but also overeating and increased intake of mainly calorie-dense and unhealthy foods.
  • Weight change - Pathological weight loss is defined as a 5% weight loss per month.
  • Insomnia or sleep disturbances - Early morning awakenings around 3-4am and difficulty falling asleep are very typical.
  • Loss of appetite for sex (decreased libido)
  • Feeling of complete lack of energy, early fatigue even after the slightest activity. Especially exhausting is the psychological load, which the patient absolutely cannot tolerate.
  • Hypobulia - The feeling that the patient has to force himself into every activity, even the routine ones.
  • Hypoactivity - A consequence of hypobulia
  • Bradypsychic thinking - Slowing of thinking, cognitive function deteriorates. Signs of dementia (depressive pseudodementia) may also occur.
  • Depressive thinking is accompanied by psychotic symptoms in cases of severe depression, called depressive delusions, which can be
    • Self-blaming - The patient blames themselves for misfortunes that affect innocent people, most often close family members, but often also complete strangers, e.g. victims of global disasters.
    • Insufficient - He or she considers himself or herself to be completely incapable.
    • Ruinous - The patient has the irrefutable idea that he or she will end up "broke". He or she fears losing all possessions and becoming poor.
    • Nihilistic - In extreme cases of depression, the patient even denies the existence of his own person, sometimes even the existence of a family member or the presence of his internal organs.
    • Hypochondriac - The patient suffers from the delusion that he has an incurable, fatal, often unknown and rare disease.

Risk of suicide

Retrospective psychiatric studies point to the serious and sad fact that up to 80% of completed suicides have some underlying affective disorder. Affective disorders, which include depression, are essentially treatable illnesses. This makes this fact even more disturbing.

Approximately 5-15% of patients with depression end their lives by suicide.

Statistically, the most common age group is men in their 70s. The cause of death is usually hanging or suffocation.

For women, the most common methods of suicide are poisoning by drugs or natural poisons, cutting or stabbing.

A number of questionnaires are used for early recognition of suicide risk.

One of the best known questionnaires is the PÖLDINGER QUESTIONNAIRE:

  1. Part:
  • Have you recently thought about the possibility of suicide?
  • Do you think about this possibility often?
  • Do you have to think about it even when you don't want to?
  • Do these thoughts force themselves on you against your will?
  • Have you ever considered the method of suicide?
  • Have you prepared for suicide?
  • Have you talked to anyone about your suicidal thoughts?
  • Have you ever attempted suicide in the past?
  • Have any of your relatives or friends committed suicide?
  • Do you feel that your situation is terrible and hopeless?
  • Does it make it difficult for you to think about anything other than your present problems?
  • Are you currently less in touch with your relatives and friends?
  • Are you interested in what is happening in your neighbourhood or at work?
  1. Part:
  • Do you enjoy your hobbies?
  • Do you have someone in your neighbourhood with whom you can talk openly and confidently about your problems?
  • Do you live with other people (family, friends)?
  • Do you feel a strong sense of responsibility towards your family and at work?
  • Are you a religious person?

With each "yes" answer in the first part of the questionnaire and with each "no" answer in the second part of the questionnaire, the risk of suicide increases.

Screening for suicide risk is essential for all patients with depression. If there is a real risk of suicide, the patient should be hospitalized immediately, even against his/her will.


The basis of the investigation of depression is the history. The history primarily examines the presence of neurovegetative symptoms, specifically changes in sleep patterns, appetite, and decreases or diurnal variations in perceived lack of energy.

Important information is also the duration of symptoms, loss of concentration (sometimes visible directly when communicating with the patient), weight loss, overuse of certain medications, etc.

These 9 symptoms are listed in the DSM-5 questionnaire.

At least five of them must be present for a diagnosis to be made:

  1. Sleep disturbance
  2. Inability to look forward to something
  3. Feelings of guilt or worthlessness
  4. Reduced energy and fatigue
  5. Impaired concentration and attention
  6. Changes in appetite and associated weight changes
  7. Psychomotor disturbances
  8. Suicidal thoughts
  9. Depressive mood

Other points of medical history include family history and current medications, social history with a focus on possible work stressors, history of addictions, drug and alcohol use, gambling, gambling, etc.

Physical examination and imaging (brain MRI) are aimed at ruling out possible organic causes of depression.

Of the laboratory examinations, the following are carried out:

  • Blood count, especially red blood cell count (depression in anaemia)
  • Thyroid stimulating hormone (TSH)
  • Vitamin B12
  • Rapid reagin reaction (RRR - syphilis screening)
  • HIV test
  • Electrolytes including calcium, phosphate and magnesium levels
  • Uric acid and creatinine
  • Liver enzymes
  • Blood alcohol level and other toxicology tests from blood and urine
  • Acid-base tests from arterial blood
  • Dexamethasone suppression test (used mainly in the diagnosis of Cushing's disease, but is also positive for depression)


The course of depressive episodes is characterised by their frequent recurrence.

Periods of acute symptoms and periods of calm, i.e. remission, alternate.

The clinical picture of depressive episodes in the same patient is essentially similar. It could be said that the patient experiences the same thing over and over again.

The acute phase of depression is usually the phase when the depression is diagnosed and treatment with antidepressants is started. This phase lasts from the start of treatment until the symptoms of depression subside.

At first, after the 6th week of treatment, we can expect a mood improvement of about 50%. After the 12th week of antidepressants, we usually observe about 80% effect of the therapy.

The next phase of therapy occurs at the moment of partial or complete resolution of symptoms. This phase is quite long and ideally lasts up to 1 year. Although antidepressants suppress the symptoms of depression, the modification of the pathology of neurotransmitters in the CNS takes much longer.

The other two phases, continuation and maintenance, are necessary to prevent recurrence of the illness and to protect the patient from the outbreak of a new depressive episode.

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