Serial dexamethasone suppression tests in psychiatric illness: Part I. A study in schizophrenia and mania

Weekly dexamethasone suppression tests (DSTs) were performed in 15 patients with schizophrenia (n = 12) and mania (n = 3) until clinical response. At initial evaluation, 53.4% of the patients were nonsuppressors, and 93.3% showed nonsuppression at least once during the treatment period. There was a tendency for DST results to normalize coincident with clinical improvement, although single peaks of DST nonsuppression occurred in several patients irrespective of clinical course. The tests did not prove useful as predictors of recovery or relapse. DST nonsuppression occurred significantly more often in severely ill patients than in moderately ill patients or in patients after recovery, emphasizing the effects of nonspecific stress factors and/or severity of illness on the DST. The cutoff point, established on the basis of DST results in 67 healthy controls, was lower than in other studies, and nonsuppression among healthy controls was associated with low dexamethasone serum levels.