Combination of NMDA-enhancing and Anti-inflammatory Treatments for Ultra-resistant Schizophrenia

Inclusion Criteria: * Have a DSM-5 (American Psychiatric Association) diagnosis of schizophrenia * Are treatment-resistant to standard treatments of at least two specific antipsychotics before clozapine treatment * Are receiving adequate trials of clozapine for more than 12 weeks but without satisfactory response * PANSS total score ≥ 70; SANS total score ≥ 40 * Have sufficient education to communicate effectively and are capable of completing the assessments of the study * Agree to participate in the study and provide informed consent Exclusion Criteria: * DSM-5 diagnosis of intellectual disability or substance (including alcohol) use disorder * History of epilepsy, head trauma, or serious medical or central nervous system diseases (other than schizophrenia) which may interfere with the study * Clinically significant laboratory screening tests (including blood routine, biochemical tests) * Pregnancy or lactation * Inability to follow protocol