Is the lack of association between cognitive complaints and objective cognitive functioning in patients with bipolar disorder moderated by depressive symptoms?

OBJECTIVES: To investigate the association between cognitive complaints and objective cognitive functioning in bipolar patients, with a focus on the moderating role of depressive symptoms.
METHODS: The association between cognitive complaints (measured by the total score and four subscales of the Cognitive Failure Questionnaire; CFQ) and objective cognitive functioning (domains of psychomotor speed, speed of information processing, attentional switching, verbal memory, visual memory and executive functioning/working memory, and the total score) was assessed in 108 euthymic (n=45) or mildly to moderately depressed bipolar patients (n=63). We studied potential moderation of this association by depressive symptoms (total score of the Inventory of Depressive Symptomatology-self rating). Analyses were performed using Pearson correlations and multiple linear regression.
RESULTS: Cognitive complaints were not associated with objective cognitive functioning, except for CFQ 'memory for names' which was positively correlated with speed of information processing (r=0.257, p=0.007). Although depressive symptoms were positively associated with cognitive complaints (total score and three subscales; p<0.01), the association between cognitive complaints and objective cognitive functioning was not moderated by depressive symptoms (p for interaction 0.054 to 0.988). LIMITATIONS: It can be argued whether the retrospective questionnaire (CFQ) is sufficiently accurate to measure the type of cognitive dysfunctions seen in bipolar patients.
CONCLUSIONS: Cognitive complaints are not associated with objective cognitive functioning, irrespective of depressive symptoms. However, cognitive complaints are indicative for depressive symptoms. Clinicians should be to be alert to depressive symptoms rather than objective cognitive problems in patients expressing cognitive complaints.