Kambuzuma Paidamoyo F, Marais Belinda
Department of Psychiatry, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
S Afr J Psychiatr. 2025 Jul 17;31:2462. doi: 10.4102/sajpsychiatry.v31i0.2462. eCollection 2025.
Stuttering, a speech disorder marked by disruptions in fluency, can be developmental or acquired. Acquired stuttering often stems from neurological causes, psychological trauma or certain medications, with antipsychotics such as clozapine implicated in several cases. Clozapine, particularly at higher doses, has been associated with dose-dependent stuttering although the precise mechanisms remain uncertain. While clozapine's effects dopamine pathways and seizure thresholds are proposed mechanisms, movement disorders such as focal dystonia and prior extrapyramidal symptoms (EPSEs) are also implicated.
A 40-year-old man with HIV, schizophrenia and a history of previous severe dystonic reaction to typical antipsychotics, developed stuttering after initiation of clozapine. His stuttering was accompanied by involuntary oral movements.
The patient's psychotic symptoms were found to be treatment-resistant, unresponsive to trials of two antipsychotics, and thus necessitating the initiation of clozapine. Following clozapine administration, the patient developed stuttering, which was unresponsive to benzodiazepine therapy and showed no abnormalities on electroencephalogram (EEG) assessment. Gradual resolution of stuttering was observed upon clozapine discontinuation and a switch to amisulpiride.
Clozapine was identified as the likely cause of stuttering in the presence of additional risk factors such as HIV and a history of EPSEs.
This case highlights the importance of recognising clozapine-induced stuttering.
口吃是一种以流畅性中断为特征的言语障碍,可分为发育性或后天性。后天性口吃通常源于神经学原因、心理创伤或某些药物,氯氮平这类抗精神病药物在多例病例中被认为与之有关。氯氮平,尤其是高剂量时,与剂量依赖性口吃有关,尽管确切机制尚不确定。虽然有人提出氯氮平对多巴胺通路和癫痫阈值的影响是其机制,但诸如局灶性肌张力障碍等运动障碍和既往锥体外系症状(EPSEs)也与之有关。
一名40岁男性,患有艾滋病、精神分裂症,既往对典型抗精神病药物有严重肌张力障碍反应史,在开始使用氯氮平后出现口吃。他的口吃伴有不自主的口腔运动。
发现该患者的精神病症状对治疗有抵抗性,对两种抗精神病药物试验均无反应,因此需要开始使用氯氮平。服用氯氮平后,患者出现口吃,对苯二氮䓬类治疗无反应,脑电图(EEG)评估未显示异常。停用氯氮平并换用氨磺必利后,口吃逐渐缓解。
在存在艾滋病和既往锥体外系症状史等额外风险因素的情况下,氯氮平被确定为口吃的可能原因。
本病例突出了认识氯氮平所致口吃的重要性。