Akkermansia muciniphila can alleviate symptoms of depressive disorder， anxiety， and neurodegenerative diseases through the gut-brain axis by regulating immunity and metabolism. However， its role in neuropsychiatric disorders is still controversial： clinical data show that this bacterium is specifically enriched in patients with autism and Parkinson's disease， suggesting that its abundance may be related to the stage of disease progression or host compensation mechanism. This paper systematically reviews the bidirectional role of this bacterium in neuropsychiatric disorders diseases such as depressive disorder and Alzheimer disease， integrates experimental and clinical evidence， explores key influencing factors including strain heterogeneity， host genetics， and intervention timing. This paper provides a basis for precise neural regulation based on the microbiome， and points out that in the future， multi-omics and clinical trials are needed to promote clinical translational research in this field.