NKTR is also increased in expression in our previous blood biomarker studies of suicide, in both males [8, 21], and females [22], as well as increased in expression in postmortem brain studies in depression [23] and in schizophrenia [24], possibly underlying the effect of stress on those disorders and, based on our new data, on decreasing memory retention and promoting AD. This evidence concerns the gene NKTR and depressive symptom measurement.