The dexamethasone suppression test (DST) and platelet monoamine oxidase (MAO) activity as predictors of psychosis in depression

Abstract

The Dexamethasone Suppression Test (DST) has been used extensively to identify patients with endogenous and/or melancholic depressions. Moreover, patients with psychotic forms of endogenous depression have been found to be more likely to have abnormal DSTs than are patients with nonpsychotic forms of these depressions (Carroll et al. 1980; Coryell et al. 1982; Rudorfer et al. 1982; Caroff et al. 1983; Evans et al. 1983; Schatzberg et al. 1983a). Focusing on the specific values of 4:00 PM postdexamethasone serum cortisol levels, rather than simply on the qualitative distinction between suppression and nonsuppression, Schatzberg et al. (1983a) showed that depressed subjects with very high cortisol levels tend to be psychotic. For example, in patients with major depression, they found psychosis in over 70% (7/9) of the patients with postdexamethasone cortisol levels over 15 kg/dl, but in less than 20% (7/36) of the patients with postdexamethasone cortisol levels less than 15 p,g/dl. Platelet monoamine oxidase (MAO) activity has also been widely studied in affective illness. Findings by Meltzer et al. (1980) and by Schildkraut et al. (1977) suggest that high platelet MAO activity might be associated with psychotic depression. particularly in female patients. Furthermore, Schatzberg et al. (1983b) found a significant association between high platelet MAO activity (37.0 nmol tryptamine deaminatedlhrimg protein) and DST nonsuppression in depressed patients. Given the apparent relationship between DST nonsuppression and psychosis in depressed patients. these findings of Schatzberg ct al. would be compatible with an association between high platelet MAO activity and psychotic depression. In the following case report. the authors suggest that the combination ot‘ an extremely