Bourque Josiane, Lakis Nadia, Champagne Julie, Stip Emmanuel, Lalonde Pierre, Lipp Olivier, Mendrek Adrianna
a Fernand-Seguin Research Centre of Louis-H. Lafontaine Hospital , Montreal , Quebec , Canada.
Cogn Neuropsychiatry. 2013;18(6):615-30. doi: 10.1080/13546805.2012.760917. Epub 2013 Jan 23.
Clozapine, the most widely used option in treatment-resistant schizophrenia, has been shown to be superior to other antipsychotic medications in improving cognitive function in patients. However, the results have not been consistent and the mechanisms underlying this effect have not been elucidated. Thus, the purpose of the present study was to evaluate verbal and nonverbal cognition (using visuospatial processing tests) in patients treated with clozapine (initially treatment resistant) and those treated with other second-generation antipsychotics, relative healthy control subjects. Furthermore, we examined neural correlates of visuospatial processing in the three groups.
Twenty schizophrenia patients treated with clozapine (TR-C group), 23 patients stabilised with atypical antipsychotics other than clozapine (NTR group), and 21 healthy control participants completed a battery of verbal and visuospatial cognitive tests. In addition, participants underwent functional magnetic resonance imaging (fMRI) while performing one of the visuospatial tests (the mental rotation task). The fMRI data were analysed separately in each group using Statistical Parametric Mapping software (SPM5).
Overall, schizophrenia patients exhibited deficit on verbal and nonverbal processing relative to the healthy controls, but we observed some interesting differences between the two groups of patients. Specifically, the NTR group performed better than the TR-C group on the Block Design and the Raven's Progressive Matrices. With respect to brain function during mental rotation, the NTR group showed significant activations in regions of the temporal and occipital cortex, whereas the TR-C patients did not. The relative deactivations associated with the task were also more robust in NTR compared to the other group of patients, despite a similar performance.
Present results suggest better visuospatial processing in the NTR relative to the TR-C group. This difference could be attributed to the treatment resistance itself or a lack of beneficial effect of clozapine relative to other atypical antipsychotics in ameliorating nonverbal abilities. Future studies of the relationship between clozapine and cognition, as well as between treatment resistance and cognition, are warranted.
氯氮平是治疗难治性精神分裂症最常用的药物，已被证明在改善患者认知功能方面优于其他抗精神病药物。然而，结果并不一致，这种作用的潜在机制也尚未阐明。因此，本研究的目的是评估使用氯氮平治疗的患者（最初为难治性）、使用其他第二代抗精神病药物治疗的患者以及相对健康的对照受试者的言语和非言语认知（使用视觉空间处理测试）。此外，我们检查了三组中视觉空间处理的神经相关性。
20例接受氯氮平治疗的精神分裂症患者（TR-C组）、23例使用除氯氮平以外的非典型抗精神病药物稳定病情的患者（NTR组）和21名健康对照参与者完成了一系列言语和视觉空间认知测试。此外，参与者在进行一项视觉空间测试（心理旋转任务）时接受功能磁共振成像（fMRI）检查。使用统计参数映射软件（SPM5）对每组的fMRI数据进行单独分析。
总体而言，与健康对照相比，精神分裂症患者在言语和非言语处理方面表现出缺陷，但我们在两组患者之间观察到了一些有趣的差异。具体而言，NTR组在积木设计和瑞文渐进矩阵测试中的表现优于TR-C组。在心理旋转过程中的脑功能方面，NTR组在颞叶和枕叶皮质区域显示出显著激活，而TR-C组患者则没有。尽管表现相似，但与任务相关的相对去激活在NTR组中也比另一组患者更明显。
目前的结果表明，NTR组相对于TR-C组具有更好的视觉空间处理能力。这种差异可能归因于难治性本身，或者氯氮平相对于其他非典型抗精神病药物在改善非言语能力方面缺乏有益效果。有必要对氯氮平与认知之间的关系以及难治性与认知之间的关系进行进一步研究。
