Sources of declarative memory impairment in bipolar disorder: mnemonic processes and clinical features.
BACKGROUND
There is mounting evidence that declarative memory processes are impaired in patients with bipolar disorder. However, predictors of the observed impairment are not well understood. This study seeks to: (i) better characterize the nature of declarative memory impairment in bipolar disorder, and (ii) determine the relationship between clinical variables and memory function in bipolar disorder.


METHODS
49 adult patients with bipolar disorder in varying mood states and 38 demographically matched healthy participants completed a comprehensive neurocognitive battery assessing general cognitive functioning, processing speed, and declarative memory. The California verbal learning test was used to characterize learning and memory functions.


RESULTS
Although patients with bipolar disorder utilized a similar semantic clustering strategy to healthy controls, they recalled and recognized significantly fewer words than controls, suggesting impaired encoding of verbal information. In contrast, lack of rapid forgetting suggests relative absence of a storage deficit in bipolar patients. While severity of mood symptomatology and illness duration were not associated with task performance, gender and family history significantly affected memory function.


CONCLUSIONS
Results suggest that declarative memory impairments in bipolar patients: (1) are consistent with deficits in learning, but do not appear to be related to different organizational strategies during learning, and (2) do not appear to be secondary to clinical state, but rather may be associated with the underlying pathophysiology of the illness.
Bearden
Carrie E
CE
Department of Psychiatry & Biobehavioral Sciences, University of California Los Angeles, 300 Building Medical Plaza, Suite 2265, Los Angeles, CA 90095, USA. cbearden@mednet.ucla.edu
Glahn
David C
DC
Monkul
E Serap
ES
Barrett
Jennifer
J
Najt
Pablo
P
Kaur
Simerjit
S
Sanches
Marsal
M
Villarreal
Veronica
V
Bowden
Charles
C
Soares
Jair C
JC
D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology / Q000523:psychology; D001931:Brain Mapping; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D005838:Genotype; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology / Q000523:psychology; D008570:Memory, Short-Term / Q000502:physiology; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology; D012153:Retention, Psychology / Q000502:physiology; D012737:Sex Factors; D013067:Speech Perception / Q000502:physiology; D013702:Temporal Lobe / Q000503:physiopathology; D014706:Verbal Learning / Q000502:physiology