A comparison of cognitive functioning in medicated and unmedicated subjects with bipolar depression.
OBJECTIVE
Neuropsychological studies of bipolar disorder reveal deficits in a variety of domains, including affective processing, memory, and sustained attention. These findings are difficult to interpret due to the potential confounding effects of mood-stabilizing medications. The present study aims to compare the cognitive performance of medicated and unmedicated subjects with bipolar depression to healthy control subjects.


METHODS
Unmedicated subjects with bipolar depression (UBD, n = 32), subjects with bipolar depression on therapeutic doses of lithium or valproic acid (MBD, n = 33), and healthy control subjects (HC, n = 52) performed neuropsychological tasks measuring affective processing, visual memory, and sustained attention. Performance measures were covaried with age and mood ratings, where applicable.


RESULTS
With regard to affective processing, the MBD group exhibited greater response latency than the UBD and HC groups. For the same task, the MBD group made more omission errors during the happy condition than in the sad condition. On a task of sustained attention, the MBD group made more errors than the HC group. There were no significant group differences on measures of visual memory.


CONCLUSIONS
Deficits in affective processing were found in the medicated group, while unmedicated subjects appear to be unaffected. In particular, the MBD group made more errors during happy conditions, indicating a potential attentional bias in subjects with bipolar depression on mood-stabilizing medications. The present study also implicates impairment in sustained attention for medicated subjects with bipolar disorder, particularly those with the type II variety.
Holmes
M Kathleen
MK
Mood and Anxiety Disorders Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
Erickson
Kristine
K
Luckenbaugh
David A
DA
Drevets
Wayne C
WC
Bain
Earle E
EE
Cannon
Dara M
DM
Snow
Joseph
J
Sahakian
Barbara J
BJ
Manji
Husseini K
HK
Zarate
Carlos A
CA
D000328:Adult; D000339:Affect / Q000187:drug effects; D000704:Analysis of Variance; D018692:Antimanic Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000188:drug therapy* / Q000503:physiopathology*; D003071:Cognition / Q000187:drug effects*; D005260:Female; D006801:Humans; D018021:Lithium Chloride / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D014635:Valproic Acid / Q000627:therapeutic use*; D055815:Young Adult
D018692:Antimanic Agents; D014635:Valproic Acid; D018021:Lithium Chloride