Numerous investigators have conducted extensive investigation in the search for biological markers in psychiatric illness. There are, as a test of q biological approach to the diagnosis of the psychiatric illness, tests for the neurotransmitters, their metabolites, and related enzymes, the neurotransmitter receptors, the neuroendocrine output and response, the membrane transport, peptides and eletrolytes. They are called the biological markers, and they are helpful for the diagnosis or differential diagnosis, choice of treatment or drugs, symptom improvement, predictor of recurrence and anticipation of suicidal attempt. These studies are among the main purposes that are pursued in the neuroscience and based on the potential utility of the biological markers mentioned above. Since 1970's, lots 01 biological markers' studies for the diagnosis, differential diagnosis or subtypes differentiation have been done but varieties of different opinions have been drawn since then through they could explain the charaters of main psychiatric illness(especially schizophrenia and mood disorder). But, the search for biological markers, including displines of neuroendoclinology and neurochemistry(neurotransmitter and thair metabolite), has yielded a number of putative trait merkers and state markers for psychayric illness. This paper aims to anticipate or evaluate the good response to the therapy(Therpeutic response) with lots of markers. Acoording to the diagnosis of lots of diseases or subtypes, we are going to review the papers, mainly concern with 'Is there any Marker' or 'Is any test possible to detect the improvement clinically?' 'Is it possible to predict the recurrence or good prognsis?' or 'Is it possible to select any drug or therapy to bring the good response?' The biological tests to review are mainly the metabolites of catecholamine neurotransmitter, and especially neuroendocrine test based on the knowledge that hormons of the adenohypophysis are influenced by activity of the cerebral or limbic neurons as well as the hypothalamus ones. Among them, author introduced some clinically available tests that are DST, TRH stimulation test(TRHST), GH stimulation test, and the urine MHPG test that can give us the evaluation of the treatment response, the predictor for recurrence or choice of drug that can bring a good response. So author discussed thair potential utility in clarifying, therapeutic, and prognostic issues in psychatric illness. We hope they'll be used and look forward to more active study on the different opinion.