Symptom profiles of biological markers in depression: a multivariate study

The dexamethasone suppression test (DST), the thyrotropin releasing hormone (TRH) test, and the ratio of plasma L-tryptophan to competing amino acids (L-TRP/CAA) were studied in relation to the 21 items of the Hamilton Depression Rating Scale (HDRS) in 123 depressed patients categorized according to DSM-III. The relationships between the biological data and the items or item clusters of the HDRS were assessed by multivariate analyses. The psychopathological correlates of increased post-dexamethasone cortisol and decreased thyroid stimulating hormone (TSH) responsivity to TRH were middle and delayed insomnia and weight loss. The symptom correlates of decreased availability of L-TRP to the brain were psychic anxiety, depersonalization, obsessions and paranoid symptoms. Core depressive symptoms, i.e. depression, loss of interest, feelings of guilt and suicidal thoughts, were not related to the biological markers.