Cognitive impairment in bipolar II disorder.
BACKGROUND
Persistent impairments in neurocognitive function have been described in bipolar disorder.


OBJECTIVE
To compare the cognitive performance of patients with bipolar II disorder with that of patients with bipolar I disorder and a healthy control group.


METHODS
The study included 71 euthymic patients with bipolar disorder (38 bipolar I, 33 bipolar II), who were compared on clinical and neuropsychological variables (e.g. executive function, attention, verbal and visual memory) and contrasted with 35 healthy controls on cognitive performance.


RESULTS
Compared with controls, both bipolar groups showed significant deficits in most cognitive tasks including working memory (DigitSpan Backwards, P=0.002) and attention (DigitSpan Forwards, P=0.005; Trail Making Test, P=0.001). Those with type II disorders had an intermediate level of performance between the bipolar I group and the control group in verbal memory (P<0.005) and executive functions (Stroop interference task, P=0.020).


CONCLUSIONS
Cognitive impairment exists in both subtypes of bipolar disorder, although more so in the bipolar I group. The best predictors of poor psychosocial functioning in bipolar II disorder were subclinical depressive symptoms, early onset of illness and poor performance on a measure related to executive function.
Torrent
Carla
C
Clinical Institute of Neuroscience, University Hospital Clinic of Barcelona, Villarroel 170, 08036 Barcelona, Spain.
Martínez-Arán
Anabel
A
Daban
Claire
C
Sánchez-Moreno
Jose
J
Comes
Mercè
M
Goikolea
José Manuel
JM
Salamero
Manel
M
Vieta
Eduard
E
D000328:Adult; D001714:Bipolar Disorder / Q000150:complications*; D003072:Cognition Disorders / Q000523:psychology*; D006801:Humans; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests