Approximately one in four people in the Netherlands will, at one point in their live, come in contact with a depression or an anxiety disorder. The burden of disease from these ailments is considerable: they account for diminished functioning, a lot of absence from work, high costs for society and even for the development of other physical illness. It is for that reason that the World Health Organisation has estimated that depression, because of its impact on quality of life, in the year 2020 will be ‘public illness number one’ in every western country.
An important reason for depression and anxiety disorders big impact on health is that of the often chronic, recurrent course of these disorders. About one third of every patient is bothered by their symptoms for two years, and often even longer. It still is not clear why complaints pass quickly with some people and continue with others. That is why the Dutch Study for Depression and Anxiety (NESDA) began in 2004. The study contains a group of about 3000 participants with and without depression and anxiety symptoms, recruited through General Practitioner offices and mental health institutions in three regions in the Netherlands. NESDA is a collaboration between various mental health institutions, universities and disciplines.
NESDA studies the long-term course of anxiety and depression disorders. Important questions that researchers hope to answer are for example: What makes people more susceptible to anxiety disorders or depressions? Why is one person depressed for three months and another for three years? Which long-term effects do depression or anxiety disorders have on daily functioning?
During the last eight years NESDA has produced more than 200 (scientific) publications and more than 20 dissertations. One of the NESDA findings include the big overlap between depression and anxiety disorders: they mutually occur with over 70 percent of the participants. Furthermore there is a clear connection between depression and anxiety and physical health. Within NESDA a lot of attention goes to genetic research and to biological research for the role of disrupted stress systems in the body. But the influence of psychological and environmental factors, such as personality or important life events, are also looked at extensively.
Based on the NESDA results we expect a better understanding of the underlying factors that account for some people being anxious en depressed while others do not. We would also like to be able to make a better estimate of which person will encounter a long course of the disorder, and what therapy works best for which person.