The effects of emotions on symptoms in fibromyalgia and the modulating role of physiology and emotion regulation. An experimental study.

Fibromyalgia is a prevalent condition that is accompanied by chronic widespread
pain and secondary symptoms such as fatigue. The condition is medically
unexplained and there is still much indistinctness regarding the maintaining
and intensifying factors of the symptoms of fibromyalgia. Emotions may be one
such factor. Outer-directed emotions such as anger may especially intensify
pain, while inner-directed emotions such as sadness may decrease pain and
increase fatigue. The impact of emotions on symptoms may depend on
physiological activation . Anger is accompanied by an increase in
noradrenaline, which leads to an increase in pain in fibromyalgia. It is
unclear whether emotions lead to a similar physiological activation in patients
with fibromyalgia and controls. Individual differences in how people handle
their emotions in daily life (emotion regulation) may also influence the
association between emotions and symptoms. Like emotion are emotion regulation
styles related to physiological activity and symptom report. Suppression of
emotions, alexithymia, and anger-in and anger-out may strengthen the
association between emotions and symptoms, while the relation may be less
strong or absent in people who generally express or reappraise their emotions.

The study aims to examine whether the emotions anger and sadness influence pain
and fatigue in female patients with fibromyalgia and a control group from the
general population and whether physiological reactivity and individual
differences in emotion regulation impact on these associations.
The study aims to answer the following research questions:
a) Does induced anger lead to heightened pain report and a reduced pain
threshold and pain tolerance in female patients with fibromyalgia and to
reduced pain report and a heightened pain threshold and pain tolerance in
female controls?
b) Does induced sadness lead to larger increases in fatigue in female patients
with fibromyalgia than in female controls?
c) Do induced anger and sadness lead to increased sympathetic and
parasympathetic activity and does this physiological activiation differ between
patients and controls?
d) Can change in symptom report be predicted from sympathetic and
parasympathetic reactivity?
e) Do individual differences in emotion regulation influence the association
between emotions and symptoms?

The study has a quasi-experimenal crossover design and takes 2 hours per
participant. Traveling expenses are paid. The experiment consists of a baseline
period and three counterbalanced conditions (recall of a neutral, angry, and
sad situation). During all conditions, noninvasive continuous physiological
assessments are performed of heart rate, blood pressure, and impedance,
emotions and symptoms are reported, and pain threshold and pain tolerance will
be determined by means of a pain measure (increasing electrical current).

Research participants will be asked to recall a neutral, angry, and sad event
from their recent past and repeated pain measurements will be conducted to
determine sensory threshold, pain threshold, and pain tolerance.

The study is considered to bring no risks for the participants. Negative
emotions will be induced, but this concerns self-selected situations from the
participant. The determination of pain threshold and pain tolerance has been
applied in different studies in chronic pain patients without problems.
Furthermore, participants can stop their participation at any moment during the
experiment and they will be debriefed after the experiment.