Impaired cognition in bipolar I disorder: the roles of the serotonin transporter and brain-derived neurotrophic factor.
BACKGROUND
Studies have proposed that cognitive deficits are present in a variety of mood states in bipolar disorder (BD). The goal of this study was to find the cognitive deficits in euthymic BD patients and to further explore possible underlying mechanisms of the deficits.


METHODS
Thirty-three healthy controls (HCs) and twenty-three euthymic BD type I patients were recruited. Single photon emission computed tomography (SPECT) with (123)I-ADAM was used to image the serotonin transporter (SERT). Ten milliliters of venous blood was drawn for the measurement of brain derived neurotrophic factor (BDNF). Cognitive functions were tested included attention, memory, and executive function.


RESULTS
We found that the SERT availability in both the midbrain and striatal regions was decreased in the BD patients compared with the HCs; however, the BDNF were not different between the two groups. There was no correlation between the SERT availability and the BDNF. Interestingly, there were statistically significant differences in sub-items of the facial memory test and the Wisconsin Card Sorting Test between the BD patients and the HCs, which showed that there was a cognitive deficit in the BD patients. However, the overall deficits in cognition were not significantly correlated with the SERT availability or the BDNF.


CONCLUSIONS
The effect of medications on cognitive function and BDNF should be considered.


CONCLUSIONS
We replicated previous findings that showed cognitive deficits in euthymic BD patients. However, the underlying mechanism of cognitive deficits in euthymic BD patients cannot be entirely explained by SERT and BDNF.
Department of Psychiatry, Taipei Veterans General Hospital & National Yang Ming University, Taipei, Taiwan. c520608@ms64.hinet.net
Yuan-Hwa
YH
Chou
Shyh-Jen
SJ
Wang
Jiing-Feng
JF
Lirng
Chun-Lung
CL
Lin
Kai-Chun
KC
Yang
Chih-Ken
CK
Chen
Chin-Bin
CB
Yeh
Mei-Hsiu
MH
Liao
D000328:Adult; D001288:Attention; D001714:Bipolar Disorder / Q000378:metabolism* / Q000523:psychology; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood* / Q000502:physiology; D016022:Case-Control Studies; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D008636:Mesencephalon / Q000378:metabolism; D008875:Middle Aged; D050486:Serotonin Plasma Membrane Transport Proteins / Q000493:pharmacokinetics* / Q000502:physiology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D019208:Brain-Derived Neurotrophic Factor; D050486:Serotonin Plasma Membrane Transport Proteins