Impaired sustained attention and executive dysfunction: bipolar disorder versus depression-specific markers of affective disorders

Methods We examined executive function, sustainedattention and short-term memory as neurocognitive domains in 18 participants with bipolardisorder in euthymic state (Beuth), 14 in depressed state (Bdep), 20 with unipolar depression (Udep) and 28 healthy control participants (HC). We conducted four-group comparisons followed by relevant post hoc analyses. Results Udep and Bdep, but not Beuth showed impairedexecutive function (p = 0.045 and p = 0.046, respectively). Both Bdep and Beuth, but not Udep, showed impairedsustainedattention (p = 0.001 and p = 0.045, respectively). The four groups did not differ significantly on short-term memory. Impairedsustainedattention and executive dysfunction were not associated with depression severity, duration of illness and age of illness onset. Only a small number of abnormal neurocognitive measures were associated with medication in Bdep and Beuth. Conclusion Impairedsustainedattention appears specific to bipolardisorder and present in both Beuth and Bdep; it may represent an objective marker of bipolardisorder. Executive dysfunction by contrast, appears to be present in Udep and Bdep and likely represents a marker of depression