Combined gas chromatographic mass spectrometric methods can be employed to assess total body turnover of norepinephrine (sum NE) and dopamine (sum DA) in human subjects and rats, and to further assess and determine the role of peripheral and central catecholamines and other biogenic amines in mental illness. We have used this method in a number of experiments. (1) We continue to gather data supporting a tendency for sum NE to be elevated in major depression. (2) We have also continued to gather data on sum DA and sum NE and their ratios in schizophrenic patients. (3) We have evaluated sum NE and DA in subjects with Norrie's disease who had a deletion of their X-chromosome. (4) Sum DA and its ratio to sum NE was also evaluated in cocaine addicts during abstinence, and in rats during withdrawal from repeated cocaine exposure. Our objective is to explore the use of these rats as animal models of schizophrenia.