Data from: The effect of depressive symptoms on cognition in patients with fibromyalgia

Background: Fibromyalgia (FM) patients frequently complain of cognitive
problems, but it remains unclear whether these cognitive complaints can be
attributed to a dysfunction of the central nervous system or if they can
be explained by other factors associated with the disease, such as
depression, anxiety and sleep dysfunction. Methods: One hundred and ten
patients with FM were compared with thirty-three patients diagnosed with a
depressive disorder (DD) and fifty healthy controls (HC). Several measures
of attention and executive functions were used to make these comparisons
and the patients were also asked to complete questionnaires on depression,
anxiety and sleep quality. Univariate analyses of covariance (ANCOVA) were
performed to identify and control confounders and multiple linear models
were used to examine the effects of fibromyalgia and depression on
cognitive measures. Results: FM and HC differed significantly with respect
to depression, anxiety and sleep dysfunction, whereas FM and DD did not
differ in terms of symptoms of depression and anxiety. However, FM was
associated with a worse quality of sleep than DD. Comparisons of cognitive
performance between groups showed that short-term and working memory and
inattention measures were only associated with symptoms of depression,
whereas selective attention was associated with both depression and
fibromyalgia, and processing speed, cognitive flexibility and inhibitory
control showed a significant interaction between depression and
fibromyalgia. Moreover, cognitive flexibility and inhibition abilities
were specifically associated with FM. Conclusion: FM patients show a
cluster of cognitive impairment in the attentional and executive domains,
although some of the symptoms observed could be explained by the severity
of the symptoms of depression, while others seem to depend on the effects
of fibromyalgia. Implications of the findings for the understanding and
management of cognitive impairment of FM patients are discussed.