Databases such as PubMed, Embase, and Scopus were used, using the following keywords: “neuron-specific enolase” OR ‘neuron-specific enolase in schizophrenia’ OR ‘neuron-specific enolase in ischemic stroke’ OR ‘neuron-specific enolase in psychiatric disorders’ OR “neuron-specific enolase in neurological diseases.” We used filters such as “clinical trial,” ‘meta-analysis,’ ‘randomized control trial,’ and “systematic review.” The literature review was conducted by three authors, working independently of each other. The gene discussed is ENO2; the disease is psychiatric disorder.