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Title
Sleepdisturbances and fatigue in the NESDA cohort.
Participants
Hoogendijk, Penninx, Van Dyck, Smit, Zitman, Nolen…
Background
Sleep disturbances and fatigue are prevalent and disabling symptoms of both
depression and anxiety disorders, especialy rumination in e.g. generalized anxiety
disorder. Many psychiatric decompensations start with sleepdisturbances. In is
unknown, however, whether such a sleepdisturbance is just the first symptom of the
disorder, or the event that challenges the disorder. In other words: is a
sleepdisturbance the cause or the consequence of e.g. depression? Do ruminating
subjects have problems falling asleep due to the content of their thoughts or do they
ruminate to fill up the time, that they can not sleep?
Sleepdisturbances are usualy treated with benzodiazapines, that frequently
result in other sleepdisturbances, drowsyness and dependence. These siteeffects
and subsequent fatigue are an importand cause of decreased labour productivity.
Therefore, the prevention and adequate treament of these disorders is of
paramount importance.
Study aim and objectives - The aim of the NESDA-sleep project is to study the
long term prognosis of sleep disturbances in anxiety and depression in order to
contribute to improved quality of care and prevention of chronicity. Within the overall
study, three study objectives are distinguished:
(1) Describing the long term prognosis of sleep disturbances in anxiety and
depression in terms of course (chronicity, development of co-morbidity, suicidal
behaviour) and public health consequences (disability, mortality, costs).
(‘descriptive psychiatric epidemiology’)
(2) Examining demographic, behavioral, physical, biological, genetic and
psychosocial determinants of the long-term prognosis of sleep disturbances in
anxiety and depression. (‘explanatory psychiatric epidemiology’)
(3) Examining whether gene expression profiles and fMRI indicators of brain
systems functioning predict the long-term prognosis of sleep disturbances in
anxiety and depression. (‘biological psychiatric research’)
Background - Sleep disturbances and fatigue are prevalent and invalidating
symptoms of both depression and anxiety disorders, especialy rumination in e.g.
generalized anxiety disorder. Many psychiatric decompensations start with
sleepdisturbances. In is unknown, however, whether such a sleepdisturbance is just
the first symptom of the disorder, or the event that challenges the disorder. In other
words: is a sleepdisturbance the cause or the consequence of e.g. depression? Do
ruminating subjects have problems falling asleep due to the content of their thoughts
or do they ruminate to fill up the time, that they can not sleep?
Sleepdisturbances are usualy treated with benzodiazapines, that frequently
result in other sleepdisturbances, drowsyness and dependence. These siteeffects
and subsequent fatigue are an importand cause of decreased labour productivity.
Therefore, the public health relevance of sleep disturbances in anxiety and
depression is undisputed. Aetiological research has yielded few risk factors that are
open to primary preventative intervention at a large scale. Given an extremely
variable natural history, the most viable route for prevention is to influence the course
in those with an unfavourable prognosis. A second route would be to influence public
health- and economic consequences, the development of co-morbidity and the
development of suicidal behaviour.
For this, data on the long term course and consequences of sleep
disturbances in anxiety and depression (objective 1), and data on factors predicting
the prognosis (objective 2) are necessary. These data are practically unavailable,
especially for anxiety disorders. Available data suggest that demographic and
psychosocial factors predict only a small portion of the variance in outcome. Clinical
factors and underlying biological factors are probably more important. As in
aetiological work, the prognosis is probably determined by interaction of
demographic, psychosocial, genetic, biological and clinical factors. No study has
been able to integrate all five domains. Recently, the technology necessary to
integrate biological and genetic measures in epidemiological studies has become
available, allowing the integration of biological and psychosocial research paradigms
within an epidemiological framework. Gene expression profiles and functional
imaging of brain structures have recently received attention since they were found to
be important for depression. However, data on their importance in terms of predicting
the course of depression and in relationship to anxiety are lacking. Therefore, we will
examine the role these two play in the prognosis of anxiety and depression
(objective 3). With regard to treatment, very little is known about the long-term care
trajectories and the factors determining the long term provision of care in those with
sleep disturbances in anxiety and depression.
Study design – The design of the NESDA study is an 8-year longitudinal cohort
study that will include 2850 persons aged 18 through 65 years and conduct
assessments at baseline and after 1, 4 and 8 years of follow-up. NESDA is designed
to be representative of those with depression and anxiety in different health care
settings and in different stages of the developmental history of the disorders.
Therefore, the sample is stratified for setting (community, primary care and
specialised mental health) and will include different phases of illness (normals, high
familial risk, first episodes and recurrent episodes of depression (Major Depressive
Disorder, minor depression and dysthymia) and anxiety (Social Phobia, Generalized
Anxiety Disorder and Panic Disorder). Because of the well-known close relationship
between anxiety and depression, both will be studied in concert. NESDA will include
both dimensional and categorical measurements of anxiety and depression as well
as a range of other medical, psychosocial and biological (incl. genetical) variables.
Objective 3 will be assessed in a subsample of 300 NESDA subjects.
Sleep and fatigue symptoms and the use of benzodiazepines and
antidepressants will be assessed at baseline and during follow-up. In the 15-item
screening instrument (N=40500?) one question is on fatigue, one on nervousness
and one on medication for anxiety, depression, stress or tension. During the baseline
(and follow-up) interview, the BENDEP questionnair for benzodiazapine dependence
will be used. This will be in addition to a regular 9-item medication questionnair.
Moreover, the 6-item self-report Insomnia Rating Scale will be used. Anxiety and
depression diagnosis will be made using the CIDI interview and disorder severity will
be assessed using the Inventory of Depressive Symptoms (IDS), the Beck anxiety
index and the fear questionnair. Especialy the IDS contains a number of items
concerning sleep and fatigue. All subjects will fil out the MDQ for bipolar symptoms.
In case unipolar depressed subjects turn out to be bipolar during the NESDA followup period, we will test them with special emphasis on sleep disturbances.
Feasibility - The NESDA consortium consists of academic and non-academic
research groups with established expertise in conducting longitudinal studies on
anxiety and depression in different health care settings. Feasibility is enhanced by
the formal consortium, intensifying existing co-operation among participating centres,
and by the opportunity to build on (i) existing research cohorts (NEMESIS and
ARIADNE), (ii) GP practices already involved in academic research, (iii) regional
mental health centers, which all participate in the consortium and (iv) the opportunity
to test procedures in an ongoing pilot study in Amsterdam (AMSTAD). The program
is designed and budgeted for ten years. The official start date of the program is
November 1, 2003.