Increased behavioural inhibition and decreased behavioural activation in whiplash-associated disorders: Associations with health outcomes.

Background: Motivation can be investigated with the BIS (Behavioural Inhibition System)/BAS (Behavioural Activation System) scale. BAS regulates the motivation to approach goal-oriented outcomes, particularly rewarding stimuli and situations, while BIS regulates escape and avoidance of unpleasant outcomes. Chronic whiplash-associated disorders (WAD) is a heterogenous pain condition with known alterations in motivated behaviour. The study aimed (1) to investigate the relationship between BIS/BAS, and pain and disability with quality of life and psychological measures in chronic WAD; (2) to determine if BIS and/or BAS mediate the relationships between pain, disability, and psychological symptoms and quality of life.

Methods: 254 chronic WAD patients participated in the study. Outcome measures were assessed using self-report questionnaires. BIS/BAS scores were compared to published normative data. Differences in health outcomes for participants within/outside normative 95% confidence intervals were compared and correlations with health measures tested. Mediation models explored bi-directional associations between stress, anxiety, depression, post-traumatic stress severity, pain catastrophizing, and quality of life with pain and disability.

Results: Participants who exceeded normative 95% confidence intervals for BIS demonstrated higher scores for pain interference, disability and all mental health measures. No mediating role of BIS/BAS on the relation between pain and disability with quality of life and health outcomes could be confirmed.

Conclusions: A comparatively large proportion of the sample exceeded the 95% confidence interval for BIS and BAS scores with associations of these scores with health outcomes, but altered motivation to approach goal-oriented outcomes appears to play only a subordinate role in chronic WAD.

Significance statement: In line with current theories, we found a large proportion (30%-50%) of patients with whiplash-associated disorders (WAD) showing signs of altered function in the Behavioural Inhibition System (BIS) and Behavioural Activation System (BAS) suggesting altered reward processing and motivation in these patients. While such altered functions showed associations with pain interference, disability and all mental health measures, reward processing could no be demonstrated as a pathogenetically relevant factor in chronic WAD patients.