Szeszko P R, Bilder R M, Dunlop J A, Walder D J, Lieberman J A
Hillside Hospital Division of North Shore-Long Island Jewish Health System, Glen Oaks, New York, USA.
Biol Psychiatry. 1999 Mar 15;45(6):680-6. doi: 10.1016/s0006-3223(98)00258-3.
Some studies have reported psychotic symptom exacerbation during "pharmacologic challenge" paradigms using dopamine agonists. Few studies, however, have examined the effects of these agonists on neurocognitive functions in patients with schizophrenia. This study assessed the effects of methylphenidate infusion on an oral word production test with demonstrated sensitivity to frontal lobe lesions, and on clinical state.
Patients were tested at two different phases; at the onset of their first-episode of schizophrenia (acute phase), and then again after they had responded to treatment and were clinically stable (stabilization phase). During each phase, patients were tested prior to and following methylphenidate infusion. Symptom clusters (i.e., positive, negative, and disorganization) were formed from SANS and SADS-C (+PD) ratings at each of these four timepoints.
Patients produced significantly more words at preinfusion and while stabilized, suggesting that overall, decreased dopamine activity was associated with better word production. Redundant errors (i.e., perseverations of previously mentioned words and production of multiple words with the same roots) increased significantly following infusion in the stabilized phase. Disorganization symptoms increased significantly following infusion, regardless of study phase.
These findings are consistent with previous theoretical and empirical findings relating dopamine activity to verbal output, a "redundancy bias" in cognitive control, and exacerbation of disorganization symptoms.
一些研究报告了在使用多巴胺激动剂的“药理学激发”范式期间精神病症状加剧。然而，很少有研究考察这些激动剂对精神分裂症患者神经认知功能的影响。本研究评估了哌醋甲酯输注对一项对额叶病变具有敏感性的口语生成测试以及临床状态的影响。
患者在两个不同阶段接受测试；在首次发作精神分裂症时（急性期），然后在他们对治疗有反应且临床稳定后（稳定期）再次测试。在每个阶段，患者在哌醋甲酯输注之前和之后接受测试。症状簇（即阳性、阴性和紊乱）由这四个时间点每个时间点的SANS和SADS-C（+PD）评分形成。
患者在输注前和稳定期产生的单词明显更多，这表明总体而言，多巴胺活性降低与更好的单词生成相关。在稳定期输注后，冗余错误（即重复之前提到的单词以及生成多个同根单词）显著增加。无论研究阶段如何，输注后紊乱症状均显著增加。
这些发现与先前将多巴胺活性与言语输出、认知控制中的“冗余偏差”以及紊乱症状加剧相关的理论和实证研究结果一致。
