On the other hand, it has been documented that concomitant treatment with a cyclooxygenase-2 (COX-2) inhibitor, celecoxib and an antipsychotic (risperidone or amisulpride) significantly improves Positive and Negative Syndrome Scale (PANSS) scores of schizophrenia patients in double-blind, placebo-controlled clinical trials [49,50,51]. Here, PTGS2 is linked to schizophrenia.