Abstract：
BACKGROUND: Vitamin B12 deficiency is primarily associated with pernicious anaemia, polyneuropathy, and spinal-cord disease, but publications on its association with hallucinations are on the rise.
METHODS: I carried out a systematic literature search on these hallucinations in PubMed, PsycINFO, and Google Scholar, up until July 1, 2023.
RESULTS: The search yielded 50 case studies published between 1960 and 2023. The hallucinations described therein are predominantly visual and/or auditory in nature, with 20% being specified as complex, compound, or panoramic. They are often described in the context of vitamin B12-related neuropsychiatric conditions such as dementia, delirium, epilepsy, psychotic disorder, schizoaffective disorder, bipolar disorder, depressive disorder, catatonia, or obsessive-compulsive disorder. In the context of such disorders, they tend to appear first and also often appear to be the first to disappear with cobalamin treatment. Within an average of 2 months, full amelioration was thus obtained in 75% of the cases and partial amelioration in the remaining 25%. Remarkably, a quarter of the cases involved therapy-resistant hallucinations that fully resolved under cobalamin monotherapy, while other neuropsychiatric manifestations of vitamin B12 deficiency disappeared in 60% of the treated cases. Only 32% of the cases involved comorbid pernicious anaemia. This suggests that two separate or diverging pathways exist for perceptual and haematological symptoms of vitamin B12 deficiency.
CONCLUSIONS: In the light of the high prevalence rate of vitamin B12 deficiency in the general population, the findings here presented should be interpreted with great caution. Nonetheless, they offer cues for further research and experimental application in clinical practice. This may be especially relevant in light of the recent increase in the popularity of vegetarianism and the recreational use of nitrous oxide (laughing gas), which are both risk factors for vitamin B12 deficiency.
METHODS: I carried out a systematic literature search on these hallucinations in PubMed, PsycINFO, and Google Scholar, up until July 1, 2023.
RESULTS: The search yielded 50 case studies published between 1960 and 2023. The hallucinations described therein are predominantly visual and/or auditory in nature, with 20% being specified as complex, compound, or panoramic. They are often described in the context of vitamin B12-related neuropsychiatric conditions such as dementia, delirium, epilepsy, psychotic disorder, schizoaffective disorder, bipolar disorder, depressive disorder, catatonia, or obsessive-compulsive disorder. In the context of such disorders, they tend to appear first and also often appear to be the first to disappear with cobalamin treatment. Within an average of 2 months, full amelioration was thus obtained in 75% of the cases and partial amelioration in the remaining 25%. Remarkably, a quarter of the cases involved therapy-resistant hallucinations that fully resolved under cobalamin monotherapy, while other neuropsychiatric manifestations of vitamin B12 deficiency disappeared in 60% of the treated cases. Only 32% of the cases involved comorbid pernicious anaemia. This suggests that two separate or diverging pathways exist for perceptual and haematological symptoms of vitamin B12 deficiency.
CONCLUSIONS: In the light of the high prevalence rate of vitamin B12 deficiency in the general population, the findings here presented should be interpreted with great caution. Nonetheless, they offer cues for further research and experimental application in clinical practice. This may be especially relevant in light of the recent increase in the popularity of vegetarianism and the recreational use of nitrous oxide (laughing gas), which are both risk factors for vitamin B12 deficiency.
摘要：
背景：维生素B12缺乏主要与恶性贫血有关，多发性神经病,和脊髓疾病，但是关于它与幻觉的关联的出版物正在增加。
方法：我在PubMed中对这些幻觉进行了系统的文献检索，PsycINFO,和谷歌学者，直到2023年7月1日。
结果：搜索产生了1960年至2023年之间发表的50个案例研究。其中描述的幻觉本质上主要是视觉和/或听觉的，20%被指定为复杂的，化合物，或全景。它们通常在维生素B12相关的神经精神疾病如痴呆的背景下被描述，谵妄,癫痫,精神病,分裂情感障碍,双相情感障碍,抑郁症,紧张症,或者强迫症.在这种疾病的背景下，它们往往首先出现，并且通常似乎是第一个消失的钴胺素治疗。平均2个月内,因此,75%的病例获得了全部改善,其余25%的病例获得了部分改善.值得注意的是,四分之一的病例涉及治疗抗性幻觉，在钴胺素单一疗法下完全消退，而维生素B12缺乏的其他神经精神表现在60％的治疗病例中消失。只有32％的病例涉及并发恶性贫血。这表明维生素B12缺乏的感知和血液学症状存在两个独立或不同的途径。
结论：鉴于一般人群中维生素B12缺乏的高患病率，这里提出的发现应该非常谨慎地解释。尽管如此，它们为临床实践中的进一步研究和实验应用提供了线索。鉴于最近素食主义的普及和一氧化二氮（笑气）的娱乐性使用的增加，这可能尤其相关。都是维生素B12缺乏的危险因素。
方法：我在PubMed中对这些幻觉进行了系统的文献检索，PsycINFO,和谷歌学者，直到2023年7月1日。
结果：搜索产生了1960年至2023年之间发表的50个案例研究。其中描述的幻觉本质上主要是视觉和/或听觉的，20%被指定为复杂的，化合物，或全景。它们通常在维生素B12相关的神经精神疾病如痴呆的背景下被描述，谵妄,癫痫,精神病,分裂情感障碍,双相情感障碍,抑郁症,紧张症,或者强迫症.在这种疾病的背景下，它们往往首先出现，并且通常似乎是第一个消失的钴胺素治疗。平均2个月内,因此,75%的病例获得了全部改善,其余25%的病例获得了部分改善.值得注意的是,四分之一的病例涉及治疗抗性幻觉，在钴胺素单一疗法下完全消退，而维生素B12缺乏的其他神经精神表现在60％的治疗病例中消失。只有32％的病例涉及并发恶性贫血。这表明维生素B12缺乏的感知和血液学症状存在两个独立或不同的途径。
结论：鉴于一般人群中维生素B12缺乏的高患病率，这里提出的发现应该非常谨慎地解释。尽管如此，它们为临床实践中的进一步研究和实验应用提供了线索。鉴于最近素食主义的普及和一氧化二氮（笑气）的娱乐性使用的增加，这可能尤其相关。都是维生素B12缺乏的危险因素。
