Email Tessa Blanken
Phone: +31 20 5665492
From heterogeneous subtypes to homogeneous subtypes – and beyond:how do different subtypes of insomnia relate to (first-) onset depression?
Insomnia is a very common health problem that affects between 6 and 33% of the population – depending on classification criteria. Past research has shown that it is remarkable difficult to pinpoint consistent characteristics and mechanisms of insomnia. A possibility for this inconsistency is that insomnia is not a uniform disorder with a singly underlying mechanism, but rather a heterogeneous disorder consisting of multiple subtypes. Given the high prevalence rates of insomnia, it is plausible that insomnia may represent a final set of seemingly similar complaints caused by different underlying mechanisms, pathways and vulnerabilities.
The aim to define different subtypes of insomnia has a long history and has led to the construction of different subtypes of insomnia, of which psychophysiological, paradoxical and idiopathic insomnia are the most common. Most of these proposed subtypes of insomnia are based on sleep characteristics, like sleep complaints or sleep duration. It has been insufficiently explored whether clear subtypes could emerge when sleep characteristics are complemented by non-sleep characteristics. Such consideration has proven to be valuable in other disorders. For example, a systematic review on subtypes of depression suggests that optimal discrimination may not be accomplished by merely focusing on the familiar defining symptoms of depression.
In the current project we consider the possibility that insomnia comes in different subtypes of pathophysiology that are reflected in traits and other stable characteristics, and not necessarily also in specificity of sleep complaints. To evaluate this possibility, we have assessed non-sleep characteristics of insomnia with respect to life history, disease and personality traits through the online Sleep Registry platform (www.sleepregistry.nl) – an online survey database with a large number of questionnaires. The first aim of the current project is to apply bottom-up, data-driven techniques to the Sleep Registry data to derive relevant, homogeneous subtypes of insomnia defined by non-sleep characteristics.
Next to the high prevalence rates of insomnia, suffering from insomnia increases the risk of developing a depression. Estimations are that 13% of people suffering of insomnia today, will suffer from depression one year later. In addition, the prevalence of depression has been increasing over the past years and the prognosis is that depression will be the prominent cause of the global burden of disease in 2030. Therefore, it is of importance to identify subgroups that are at high risk for developing a depression. Insomnia is one of the strongest risk factors for depression that may be best modifiable. Thus, the second aim of this project is to assess how different subtypes of insomnia relate to the onset of depression.
In sum, the current project aims to apply bottom-up, data-driven techniques to derive relevant subtypes of insomnia defined by non-sleep characteristics. This understanding of subtypes hopefully leads to more accurate classification of people suffering from insomnia with the ultimate goal to provide better, and more precise treatment. In addition, knowledge of relevant, homogeneous subtypes might offer more insights in who is at risk for depression, enabling intervention of insomnia and thereby hopefully the prevention of depression.
Prof. Eus van Someren &Prof. Denny Borsboom
1 October 2015 – 1 January 2020