Antibody-mediated encephalitides are a group of inflammatory brain diseases characterized by neuropsychiatric symptoms and associated with antibodies against neuronal cell-surface proteins, ion channels, or receptors. These diseases are distinct from traditional autoimmune disorders like systemic lupus erythematosus and other paraneoplastic disorders. They occur in all age groups, with some affecting children and young adults. Common clinical features include behavioral changes, psychosis, seizures, memory deficits, and autonomic dysfunction. Diagnosis is often confirmed by laboratory tests, and prompt treatment leads to improvement or recovery in most cases. The most common forms of antibody-mediated encephalitides include anti-NMDAR encephalitis and limbic encephalitis. Anti-NMDAR encephalitis predominantly affects children and young adults, with a female predominance. It is associated with ovarian teratomas in females and presents with psychiatric symptoms, seizures, and cognitive deficits. Limbic encephalitis is more common in older adults and is associated with various antibodies, including LGI1, GABA_BR, and AMPAR. It often presents with confusion, behavioral changes, and memory impairment. The mechanisms of these diseases involve antibodies binding to extracellular epitopes of cell-surface proteins, leading to reversible neuronal dysfunction. The pathogenesis is influenced by the type of antibody, with some causing direct neuronal damage and others involving T-cell mechanisms. Treatment typically includes immunotherapy such as glucocorticoids, intravenous immune globulin, and rituximab. Early tumor removal is crucial for favorable outcomes, especially in cases associated with tumors. The frequency of these diseases is estimated at 5-8 cases per 100,000 people annually, with a significant portion of cases remaining undiagnosed. Anti-NMDAR encephalitis is the most common autoimmune encephalitis in young individuals, while LGI1 encephalitis is the second most common. These diseases can overlap with other demyelinating syndromes, leading to complex clinical presentations. Future research focuses on understanding the pathogenic mechanisms, identifying biomarkers, and developing new treatment strategies. Studies suggest that antibody effects on brain circuitry and long-lived plasma cells contribute to the prolonged course of these diseases. Understanding how antibodies cause symptoms, such as psychosis, may provide insights into other psychiatric disorders.Antibody-mediated encephalitides are a group of inflammatory brain diseases characterized by neuropsychiatric symptoms and associated with antibodies against neuronal cell-surface proteins, ion channels, or receptors. These diseases are distinct from traditional autoimmune disorders like systemic lupus erythematosus and other paraneoplastic disorders. They occur in all age groups, with some affecting children and young adults. Common clinical features include behavioral changes, psychosis, seizures, memory deficits, and autonomic dysfunction. Diagnosis is often confirmed by laboratory tests, and prompt treatment leads to improvement or recovery in most cases. The most common forms of antibody-mediated encephalitides include anti-NMDAR encephalitis and limbic encephalitis. Anti-NMDAR encephalitis predominantly affects children and young adults, with a female predominance. It is associated with ovarian teratomas in females and presents with psychiatric symptoms, seizures, and cognitive deficits. Limbic encephalitis is more common in older adults and is associated with various antibodies, including LGI1, GABA_BR, and AMPAR. It often presents with confusion, behavioral changes, and memory impairment. The mechanisms of these diseases involve antibodies binding to extracellular epitopes of cell-surface proteins, leading to reversible neuronal dysfunction. The pathogenesis is influenced by the type of antibody, with some causing direct neuronal damage and others involving T-cell mechanisms. Treatment typically includes immunotherapy such as glucocorticoids, intravenous immune globulin, and rituximab. Early tumor removal is crucial for favorable outcomes, especially in cases associated with tumors. The frequency of these diseases is estimated at 5-8 cases per 100,000 people annually, with a significant portion of cases remaining undiagnosed. Anti-NMDAR encephalitis is the most common autoimmune encephalitis in young individuals, while LGI1 encephalitis is the second most common. These diseases can overlap with other demyelinating syndromes, leading to complex clinical presentations. Future research focuses on understanding the pathogenic mechanisms, identifying biomarkers, and developing new treatment strategies. Studies suggest that antibody effects on brain circuitry and long-lived plasma cells contribute to the prolonged course of these diseases. Understanding how antibodies cause symptoms, such as psychosis, may provide insights into other psychiatric disorders.