Depression and anxiety are two very common disorders and represent the most frequently diagnosed psychiatric nosographic categories. They appear inextricably connected to each other both in clinical psychiatric and non-specialist clinical practice. We commonly hear of “anxious depression” or “anxiety-depressive syndrome”, but what is really the relationship between these two psychopathological conditions? For seeking treatment for depression this is the best deal.
To try to give an answer to this question let’s start with some literature data: 350 million people in the world suffer from depression and 265 million suffer from anxiety, with a prevalence calculated on the entire population of 4.4% and 3.6%. These data vary widely in different countries, especially depending on the socioeconomic level: anxiety and depression are more frequent in high-income countries than in developing countries and the risk of manifesting an anxious or depressive disorder is lower in eastern and greater countries in countries at war.
Like depression, anxiety disorders also affect predominantly women (4.6% vs 3.6%), and young people. The comorbidity between anxiety and depression is very frequent, and can occur at any age, from childhood to adulthood:
- Several epidemiological studies have shown that over 50% of patients with a depressive disorder during their lifetime develop an anxiety disorder, especially generalized anxiety disorder and panic disorder.
- 85% of depressed patients manifest anxious symptoms, such as alertness, panic attacks, free or somatised anxiety and phobias. 90% of subjects with an anxiety disorder experience depressive symptoms or a major depressive disorder in comorbidity, with a risk during life between 50% and 65% in patients with a panic disorder, between 8% and 39% in patients with a generalized anxiety disorder and between 34% and 70% in patients with social phobia.
Lifetime prevalence of the comorbidity of an anxiety disorder in patients with major depression
In 31% of the cases the anxiety disorder precedes the depressive episode, with an onset between one and ten years before, representing the strongest predictor of a secondary depressive disorder.
These data account for the considerable socio-economic impact, as well as the important consequences in terms of “loss of health” caused by these disorders. It has been estimated that currently depression is the fourth cause of disability in the world; according to the projections it will rise to second place in 2020 and the first in 2030. Anxiety disorders represent the sixth global cause of non-fatal health loss ( non-fatal health loss ) and appear in the ranking of the ten causes of YLD. Anxiety and depression are even more disabling when they occur simultaneously. The prognosis, and its impact on global functioning, seems to worsen in cases where there is comorbidity; the overlap of anxious symptoms, or of an anxiety disorder, accelerates, worsens, and lengthens the course of the depressive episode, determining:
- a greater severity of depressive symptoms, as shown from the results of psychometric tests such as the Hamilton Rating Scale for Depression (HAM-D), the Beck Depression Inventor
- a longer duration of the episode with an increased risk of chronic illness
- a greater suicidal risk
- a greater abuse of alcohol or drugs
- lower working and social functioning
- less response to short and long term drug treatments
- greater access to health services. The anxious symptoms also frequently remain as residual symptoms of the depressive episode, hesitating in a worse prognosis.