Affective instability, conceptualized as fluctuations in mood over time, has been related to ill-health and psychopathology. In this study, we examined the role of affective instability on daily pain outcomes in 70 patients with chronic pain (Mage = 49.7 years; 46 females) using an end-of-day diary. During a baseline phase, patients completed self-reported questionnaires of pain severity, pain duration, disability, depression, and anxiety. During a subsequent diary phase, patients filled out an electronic end-of-day diary over 14 consecutive days assessing daily levels of pain severity, disability, cognitive complaints, negative affect (NA) and positive affect. Affective instability was operationalized as the mean square of successive differences in daily mood (separately for NA and positive affect), which takes into account the size of affective changes over consecutive days. Results indicated that NA instability was positively associated with daily disability, beyond the effects of daily pain severity. Furthermore, NA instability moderated the relationship between daily pain severity and daily disability and the relationship between daily pain severity and daily cognitive complaints. Positive affect instability, however, showed to be unrelated to all outcomes. Current findings extend previous results and reveal the putative role of affective instability on pain-related outcomes and may yield important clinical implications. Indeed, they suggest that targeting NA instability by improving emotion regulation skills may be a strategy to diminish disability and cognitive complaints in patients with chronic pain.
Higher levels of affective instability, ie, frequent and large mood shifts over time, relate to worse daily pain outcomes in patients with chronic pain.
aInstitute for Health and Behaviour, INSIDE, University of Luxembourg, Esch-sur-Alzette, Luxembourg
bDepartment of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
cSchool of Psychology, Australian Catholic University, New South Wales, Australia
dResearch Group of Quantitative Psychology and Individual Differences, University of Leuven, Leuven, Belgium
eSection of Psychology, Lillehammer University College, Lillehammer, Norway
fResearch Group Health Psychology, University of Leuven, Leuven, Belgium
gResearch Group on Health Psychology, Department of Psychosomatic Medicine, Division of Surgery and Clinical Neuroscience, Oslo University Hospital, Rikshospitalet, Oslo, Norway
Corresponding author. Address: University of Luxembourg, 11, Porte des Sciences, Esch-sur-Alzette 4366, Luxembourg. Tel.: + 352 4666 44 9249; fax: +352 4666 44 9535. E-mail address: firstname.lastname@example.org (S. Rost).
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Received September 28, 2015
Received in revised form March 20, 2016
Accepted April 04, 2016