THE DEXAMETHASONE SUPPRESSION TEST IN SCHIZOPHRENIA

Background. Cortisol non-suppression following the dexamethasone suppr ession test (DST) has been found to a variable extent in schizophrenia . The aetiology is unclear but may be related to depression or negativ e symptoms. Methods. The DST was administered to 64 patients with DSM- IV schizophrenia. All patients were screened for DSM-IV major depressi on and rated on the Hamilton Rating Scale for Depression (HRSD), Scale for Assessment of Negative Symptoms (SANS) and the Brief Psychiatric Rating Scale (BPRS). Results. DSM-IV criteria for major depression was fulfilled by 36% of the patients and 42% of patients had a history of parasuicide. Four patients had undetectable levels of dexamethasone a nd were excluded from the endocrine analyses. Only one remaining patie nt had a cortisol level above the cut-off point (> 138 nmol/l), indica ting escape from dexamethasone suppression. The postdexamethasone cort isol level correlated significantly with HRSD and BPRS scores but not with the SANS. The SANS and HRSD scores were not correlated, but they were independently correlated with the BPRS score. Conclusions. In con trast to some other work, rates of dexamethasone non-suppression were very low; together with the high rates of depression, this suggests th at depression in schizophrenia may have a different neuroendocrine pro file from major depressive disorders. Failure to measure dexamethasone levels can be misleading.