Deficiência de Vitamina B12 e Manifestações Neuropsiquiátricas: Bases Neurobiológicas, Evidências Clínicas e Implicações Terapêuticas
Deficiência de Vitamina B12 e Manifestações Neuropsiquiátricas: Bases Neurobiológicas, Evidências Clínicas e Implicações Terapêuticas
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DOI: https://doi.org/10.22533/at.ed.5541326110511
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Palavras-chave: Vitamina B12; Neuropsiquiatria; Depressão; Saúde mental; Homocisteína; Psiquiatria nutricional.
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Keywords: Vitamin B12; Neuropsychiatry; Depression; Mental health; Homocysteine; Nutritional psychiatry.
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Abstract: Vitamin B12 deficiency is an important public health problem and one of the leading potentially reversible causes of neurological and neuropsychiatric disorders. Although traditionally associated with megaloblastic anemia, growing evidence indicates that psychiatric and cognitive manifestations may precede hematological abnormalities, contributing to delayed diagnosis. This book chapter provides an updated review of the neurobiological mechanisms underlying vitamin B12 deficiency, its association with neuropsychiatric manifestations, and the current diagnostic and therapeutic implications reported in the scientific literature. The chapter was developed through a narrative review based primarily on studies published between January 2021 and March 2026 retrieved from the PubMed/MEDLINE database. Key topics include cobalamin metabolism, hyperhomocysteinemia, impaired cellular methylation, defective myelin synthesis, neuroinflammation, and disturbances in monoaminergic neurotransmission, all of which may contribute to depression, anxiety, psychosis, cognitive impairment, sleep disorders, and other neuropsychiatric conditions. Emerging clinical issues, such as functional vitamin B12 deficiency associated with recreational nitrous oxide use, are also discussed, together with current diagnostic challenges and available evidence regarding vitamin B12 supplementation. Overall, current evidence supports the inclusion of vitamin B12 assessment in the clinical evaluation of patients presenting atypical, persistent, or treatment-resistant neuropsychiatric symptoms, particularly those with nutritional or metabolic risk factors, allowing timely diagnosis and potentially reversible therapeutic interventions.
- Valmin Ramos da Silva
- Greice Kelly Alves Reis
- Thiago Correa de Sá Ricardo
- Mateus Henrique Oliveira de Souza
- Ariselma Magalhães Peçanha
- Janine Pereira-Silva
- Joel Alves Lamounier
- Wendell Costa Bila