Background and aims: Dysregulation in serotonergic and noradrenergic systems may be implicated in the mechanisms underlying pain-related cognitive impairment in people with chronic whiplash-associated disorders (CWAD). This study aimed to unravel the role of serotonergic and noradrenergic descending pathways in cognition and their possible added value in the effect of a submaximal aerobic exercise on cognitive functioning in CWAD. 
Methods: In people with CWAD (n=25), endogenous descending serotonergic and noradrenergic inhibitory mechanisms were modulated by using respectively a single dose of a selective serotonin reuptake inhibitor (SSRI = Citalopram) and a selective norepinephrine reuptake inhibitor (NRI = Atomoxetine). Cognitive performance and cognitive symptoms were studied at rest and in response to exercise (1) without any medication intake, (2) after the intake of Citalopram, and (3) after the intake of Atomoxetine. 
Results: After Atomoxetine intake, choice reaction time improved and patients reported less severe memory problems compared to the no medication day (p < .05). When performing pairwise comparisons, improvements in selective attention, and reduced memory problems were found postexercise for the no medication condition (p < .05). In contrast, after intake of Citalopram or Atomoxetine, both selective and sustained attention worsened postexercise (p < .05). 
Conclusions: A single dose of Atomoxetine reduced memory complaints and improved selective attention in people with CWAD. However without medication intake, cognitive functioning improved postexercise whereas both centrally-acting medications worsened cognitive performance of people with CWAD in response to a submaximal aerobic exercise.

BRAIN NEUROTRANSMISSION, EXERCISE AND COGNITIVE FUNCTIONING IN PEOPLE WITH CHRONIC WHIPLASH-ASSOCIATED DISORDERS: A RANDOMIZED CONTROLLED CROSSOVER STUDY