Depression (mood)

In a 2011 international comparative study, the prevalence of depression in high-income countries was compared with that in middle- and low-income countries. The lifetime prevalence was 14.9% in the first group (ten countries) and 11.1% in the second group (eight countries). The ratio of women to men was approximately 2:1.

A meta-analysis of 26 studies with data from 60,000 children born in 1965-1996 found a prevalence of 2.8% for the under-13 age group and 5.6% for the 13-18 age group (girls 5.9%, boys 4.6%).

The burden of disease caused by depression, for example in the form of incapacity to work, inpatient treatment and early retirement, has risen sharply in Germany in recent years. It is assumed that the actual incidence of illness has changed much less seriously and that the increased incidence is due to better recognition and less stigmatisation of people with mental disorders. The diagnostic criteria for a mental disorder, which have become lower-threshold over time, are also critically discussed as a partial cause. Results of long-term studies on the other hand, however, rather speak for a real increase, which is associated with various societal influencing factors.

According to health insurance data, younger generations in Germany also appear to be more at risk of suffering from a mental disorder in the course of their lives. According to data from Techniker Krankenkasse, the average duration of incapacity to work among insured sufferers was 64 days in 2014 (in comparison: an average of 13 days for all diagnoses). Of the ten groups with the highest sickness rates, seven belong to the occupational area of health, social services, teaching and education. By far, employees in call centres top the list; followed by geriatric nurses and nurses, educators and childcare workers, public administration employees and employees in the security industry. Comparatively less vulnerable are university lecturers, software developers and doctors. Women are affected almost twice as often as men. From 2000 to 2013, the number of prescribed daily doses of antidepressants almost tripled. In regional terms, Hamburg (1.4 days of incapacity to work per insured employee), Schleswig-Holstein and Berlin (1.3 days each) top the list. In Hamburg, 9.2 percent of the total days of incapacity to work are due to depression. In southern and eastern Germany, the rates are lower on average. Among students, previously considered a relatively healthy group, 17 percent (about 470,000 people), mainly older ones, are now affected by a psychiatric diagnosis, according to Barmer GEK.

Symptoms

In 2011, several professional associations such as the German Society for Psychiatry and Psychotherapy, Psychosomatics and Neurology (DGPPN) developed a health care guideline on the topic of depression. It recommends distinguishing between three main and seven additional symptoms for diagnosis according to ICD-10.

Diagnostic symptoms

The main symptoms are:

1. Depressed mood: Depression is characterized by mood constriction or, in major unipolar depression, the "feeling of numbness" or the feeling of persistent inner emptiness.
2. Loss of interest and joylessness: loss of capacity for joy or sadness; loss of affective resonance, that is, the patient's mood cannot be lightened by encouragement.
3. Lack of drive and increased fatigability: Another typical symptom is drive inhibition. In a severe depressive episode, the affected person's drive can be so severely inhibited that they can no longer perform even the simplest activities such as personal hygiene, shopping or washing up.

The additional symptoms are:

1. reduced concentration and attention
2. reduced self-esteem and self-confidence (feeling of insufficiency)
3. Guilt and feelings of inferiority
4. negative and pessimistic outlook on the future (hopeless): Characteristic are exaggerated worry about the future, under certain circumstances exaggerated anxiety caused by petty disorders in the area of one's own body (see hypochondria), the feeling of hopelessness, helplessness or actual helplessness
5. Suicidal thoughts or actions: Severely affected individuals often feel a complete lack of meaning in their lives. Often this agonizing state leads to latent or acute suicidal tendencies.
6. Sleep disorders
7. reduced appetite

Possible other symptoms

Furthermore, a somatic syndrome may also be present:

• lack of ability to react emotionally to the environment
• early morning awakening: Sleep is disturbed in the form of premature awakening, at least two hours before the usual time. These sleep disturbances are an expression of a disturbed 24-hour rhythm. The disturbance of the chronobiological rhythm is also a characteristic symptom.
• Morning low: Often the patient feels particularly bad in the morning. In a rare variant of the disease, the reverse is true: a so-called "evening low" occurs, i.e. the symptoms intensify towards evening and falling asleep is difficult or only possible towards morning.
• psychomotor inhibition or agitation: inhibition of movement and initiative is often accompanied by inner restlessness, which is physically perceived as a feeling of suffering and can be very distressing (silent excitation, silent panic).
• marked loss of appetite,
• Weight loss, weight gain,
• sexual interest may also diminish or disappear (loss of libido).

Depressive illnesses are occasionally accompanied by physical symptoms, so-called vital disorders, pain in very different parts of the body, most typically with an agonizing feeling of pressure on the chest. During a depressive episode, the susceptibility to infection is increased. Social withdrawal is also observed, thinking is slowed down (inhibition of thinking), senseless circling of thoughts (compulsive brooding), disturbances of the sense of time. Often there is irritability and anxiety. In addition, there may be hypersensitivity to sounds.

As a review from 2019 points out, in addition to affective features, impairments in depression can also affect cognitive features such as control processes (executive functions), learning, memory, processing speed and attention. However, the focus in dealing with depression is usually on affective features, although attention deficits in particular have a very negative impact on functioning in everyday life. In contrast to other symptoms of depression, attention does not improve in most patients with current forms of treatment, particularly SSRIs. In contrast, medications that target catecholamines (e.g., dopamine, norepinephrine) may benefit improved attention span.

Severity

The severity is classified according to ICD-10 according to the number of symptoms:

• mild depression: two main symptoms and two additional symptoms
• moderate depression: two main symptoms and three to four additional symptoms
• major depression: three main symptoms and five or more additional symptoms

Sex differences

The symptoms of depression can be expressed in different ways depending on gender. The differences in the core symptoms are small. Whereas in women, phenomena such as despondency and brooding are more likely to be observed, in men there are clear indications that depression can also be reflected in a tendency towards aggressive behaviour. In a 2014 study, the different manifestations in women and men were linked to differences in the biological systems of the stress response.