Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
BMC Psychiatry. 2013 Jun 7;13:165. doi: 10.1186/1471-244X-13-165.
Cognitive deficits have been documented in patients with bipolar disorder. Further, it has been suggested that the degree and type of cognitive impairment differ between bipolar I and bipolar II disorder, but data is conflicting and remains inconclusive. This study aimed to clarify the suggested differences in cognitive impairment between patients with bipolar I and II disorder in a relatively large, clinically stable sample while controlling for potential confounders.
67 patients with bipolar I disorder, 43 with bipolar II disorder, and 86 randomly selected population-based healthy controls were compared. A number of neuropsychological tests were administered, assessing verbal and visual memory and executive functions. Patients were in a stable phase during testing.
Patients with bipolar type I and type II were cognitively impaired compared to healthy controls, but there were no statistically significant differences between the two subtypes. The strongest predictor of cognitive impairment within the patient group was current antipsychotic treatment.
The present study suggests that the type and degree of cognitive dysfunction is similar in bipolar I and II patients. Notably, treatment with antipsychotics - but not a history of psychosis - was associated with more severe cognitive impairment. Given that patients with bipolar I disorder are more likely to be on antipsychotic drugs, this might explain why some previous studies have found that patients with type I bipolar disorder are more cognitively impaired than those with type II.
双相情感障碍患者存在认知缺陷。此外，有人认为双相情感障碍 I 型和 II 型之间的认知损伤程度和类型存在差异，但数据存在矛盾，仍无定论。本研究旨在在控制潜在混杂因素的情况下，在相对较大的、临床稳定的样本中阐明双相情感障碍 I 型和 II 型患者认知损伤方面的差异。
将 67 名双相情感障碍 I 型患者、43 名双相情感障碍 II 型患者和 86 名随机选择的基于人群的健康对照者进行比较。采用多项神经心理学测试评估言语和视觉记忆及执行功能。患者在测试期间处于稳定期。
与健康对照组相比，双相情感障碍 I 型和 II 型患者的认知能力受损，但两种亚型之间无统计学差异。在患者组中，认知损伤的最强预测因子是当前使用的抗精神病药物。
本研究表明，双相情感障碍 I 型和 II 型患者的认知功能障碍类型和程度相似。值得注意的是，抗精神病药物治疗——而非精神病病史——与更严重的认知损伤相关。由于双相情感障碍 I 型患者更有可能使用抗精神病药物，这可能解释了为什么一些先前的研究发现，双相情感障碍 I 型患者的认知损伤比 II 型患者更严重。
