Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093-0664, USA.
Psychol Med. 2012 Jul;42(7):1409-16. doi: 10.1017/S0033291711002662. Epub 2011 Dec 9.
Few studies have examined the short-term course of cognitive impairments in bipolar disorder (BD). Key questions are whether trajectories in symptoms covary with cognitive function and whether BD is associated with increased intra-individual variability in cognitive abilities.
Forty-two out-patients with BD and 49 normal comparison (NC) subjects were administered a battery of neuropsychological tests at baseline, 6, 12 and 26 weeks, along with concurrent ratings of depressive and manic symptom severity. Mixed-effects regressions were used to model relationships between time, diagnosis and symptom severity on composite cognitive performance. Within-person variance in cognitive functioning across time was calculated for each subject.
BD patients had significantly worse performance in cognitive ability across time points, but both groups showed significant improvement in cognitive performance over repeated assessments (consistent with expected practice effects). BD was associated with significantly greater intra-individual variability in cognitive ability than NCs; within-person variation was negatively related to baseline cognitive ability in BD but not NC subjects. Changes in affective symptoms over time did not predict changes in cognitive ability.
Moderate changes in affective symptoms did not covary with cognitive ability in BD. The finding of elevated intra-individual variability in BD may reduce capacity to estimate trajectories of cognitive ability in observational and treatment studies.
鲜有研究探讨双相障碍（BD）患者认知障碍的短期病程。关键问题是症状轨迹是否与认知功能相关，以及 BD 是否与认知能力的个体内变异性增加相关。
42 名门诊 BD 患者和 49 名正常对照组（NC）受试者在基线、6、12 和 26 周时接受了一系列神经心理学测试，同时对抑郁和躁狂症状严重程度进行了评估。混合效应回归用于模拟时间、诊断和症状严重程度对综合认知表现的关系。为每位受试者计算了跨时间点的认知功能的个体内方差。
BD 患者在认知能力方面的表现随着时间的推移明显变差，但两组在重复评估中均表现出认知表现的显著改善（符合预期的练习效应）。BD 患者的认知能力个体内变异性明显大于 NC 组；BD 患者的个体内变异性与基线认知能力呈负相关，但 NC 组无此相关性。随着时间的推移，情感症状的变化并不能预测认知能力的变化。
随着时间的推移，情感症状的适度变化并不能与 BD 患者的认知能力相关。BD 中个体内变异性增加的发现可能会降低在观察性和治疗研究中估计认知能力轨迹的能力。
