Bipolar I patients with and without a history of psychotic symptoms: do they differ in their cognitive functioning?

Recently, many reports have consistently demonstrated cognitive deficits in patients with bipolar disorder (BD), but their relationship with symptomatology, specifically psychotic symptoms, remains unclear. Our main hypothesis was that a history of hallucinations and/or delusions in the course of BD-I is associated with severe cognitive deficits. We investigated several cognitive functions (memory, attention, verbal fluency and executive functions) in 18 BD-I patients with a history of psychotic symptoms (HPS+), 17 BD-I patients without a history of psychotic symptoms (HPS-), 33 schizophrenic patients and 26 healthy control subjects. Both groups of BD-I patients were more impaired than the normal controls in attention, verbal memory, verbal fluency and executive functions. Only HPS+ BD-I patients showed more difficulties in completing the Stroop test than nonpsychotic bipolar patients. Nevertheless, after adjustment for the effects of current psychopathology, this difference disappeared. Schizophrenic subjects showed worse performance than BD-I subjects in verbal memory and verbal fluency. These results suggest that a history of psychotic symptoms in bipolar I disorder may not be associated with more cognitive deficits. Further research on euthymic bipolar patients with and without HPS is required to confirm these findings.