The dynamical network approach of chronic stress.

Traditional approaches in research in the field of stress and stress related
disorders have led to fragmented knowledge (9, 10).
Therefore we adopt a scientifically fundamentally different research approach
in this field: the dynamic network approach. This dynamical network approach is
originating in the complexity approach of science. In complexity science the
behaviour of a system or model (complex systems) is studied. In a complex
system, or complex adaptive system, the constituent parts interact in mutually
various ways and these interactions obey local rules. There exists no centrally
applied rules to steer these interactions. The total of local interactions
determine the behaviour of the whole system. This phenomenon is called
emergence (15, 16, 17, 18, 19, 20).
In this study we approach the stress system (alert system) as a complex
adaptive system, in which the constituent parts influence each other and
interact in various and multiple ways and are continuously prone to change in
time (dynamic). We consider the stress system in terms of a network in which
the parts are continuously in interaction and change in time, depending on what
happens in the environment of the complex adaptive system.
Complex adaptive systems experience change under the stimuli coming from its
environment, but have a certain resilience to change (21, 22, 23, 24, 25).
However, when the stimuli from the environment become larger and stronger and
more frequent, there will be a point at which the complex adaptive system will
show a radical change. This radical change is called a critical phase
transition, in which the system flips over towards another state or phase,
which takes place at a so called tipping point (bifurcation point) (21, 22, 23,
24, 25).
This critical phase transition is exactly what we think happens in chronic
stress: the stress stimuli in the environment become so strong an frequent,
that the system approaches the tipping point and undergoes a critical phase
transition towards another phase (chronic stress phase) and finally towards
disease.
The constituent parts of a complex adaptive system show early warning signals
when approaching the tipping point (27, 28, 29). These early warning signs can
be measured. In this study we want to detect and measure these early warning
signs. To be able to make chronic stress and its early warning signs visible
and more tangible by looking at these phenomena as a dynamic network is
important, because sofar traditional approaches failed to picture a clear map
towards progress, which is really needed, since overstrain, burn out and other
stress-related disorders have a high prevalence and come with high costs, not
only in the Netherlands, but also internationally (1, 2, 3, 4).

The cause is the continuous wear and tear of daily life and continuing stimuli
and strain, which has become normal in our busy times (5).
Repeated and long-lasting exposure to stressors, resulting in semi-continuous
activation of our stress system in some periods during life aren*t only a
likely cause of overstrain and burn out, but play also a role in developing
musculoskeletal disorders and cardiovascular disease.

Chronic stress doesn*t only effect health directly, but also indirectly by
predisposing individuals to unhealthy life styles (5, 7).
Stressors and activation of the stress system effect health, work and
functioning (5, 6, 7). In the Netherlands it is estimated that at least one
third of work absenteïsm is associated with psychological complaints because of
stress related factors (8).

Scientific research in this field has been difficult and fragmented (9, 10),
since our stress system is such a complicated system, especially in relation to
our (private and working) environment. Not surprisingly, since the human stress
system has so many different aspects, which have been developed by the forces
of evolution (13) and which are intertwined in a very complex way.
The last years at least two theoretical notions of chronic stress have been
developed: the allostatic load theory and the cognitive activation theory of
stress (7, 10, 11, 12). A third important theory in stress research is the
*stress adaptation model* theory (26), stating that different clinical entities
like burn out, overstrain, fibromyalgia, chronic musculoskeletal complaints and
chronic fatigue syndrome might have at their origins the same mechanisms of
pathophysiology.

More light should be shed on the phenomenon of chronic stress as a costly
factor in our modern society, with its overload of external stimuli of
especially psychological character as well as of internal mental origin. The
classical research has been successful, but could not elicit the reasons why
one individual develops chronic stress, where another individual does not and
could so far not explain those aspects of chronic stress, we need to understand
to be able to really prevent and treat chronic stress. The stress system has
extensively been investigated, but until now with classical scientific research
methods, leading to research where isolated variables of stress are
investigated, where all of the aspects and variables which influence the stress
phenomenon are very densely interrelated (14). This makes it difficult to
unravel the human stress system and the development of chronic stress, so that
new ways of research are needed and must be explored. One of the new and
promising approaches in research is the complexity approach or dynamical
network approach, using the views and combined forces of various fields in
science as is usual in what is called the science of complexity, a field of
science that by its mere nature requires interdisciplinary collaboration. The
idea of complexity is associated with a large number of phenomena we can
observe in nature, in society, in laboratory and in computer models (15, 16,
17, 18, 19, 20).

The primary research aim is to identify the adaptation system as a dynamical
network or complex adaptive system in which the constituent parts interact and
are showing critical phases via critical phase transitions from a disease phase
with serious health complaints to a post disease phase with chronic stress less
complaints and from there back to a healthy state during adequate treatment.

This study concerns an observational, nonrandomized investigation between a
group of patients who suffer from chronic stress and / or disease and receiving
care as usual and a group of healthy volunteers to the question whether chronic
stress can be considered as a process in which the adaptation system shows
critical
phase transitions from a disease phase via one or more critical phases towards
a healthy, normal phase.

Bruises after venipuncture and vasovagal reflex.