Biological markers as classifiers for depression: a multivariate study.
1. Delta TSH, REM latency, 4 pm and 11 pm post-dexamethasone cortisol values were determined after a wash-out period in a group of 74 non-selected depressed patients who were diagnosed (according to RDC with the SADS) as follows: 46 definite and 10 probable MD, 4 minor and 14 intermittent depression. 2. These biological variables, as well as gender, age and basal TSH were introduced in a principal component analysis. The four first PC scores explaining up to 77% of the data set were further calculated for each patients and used in a cluster analysis. A three clusters solution was retained. 3. DST escape and increased TSH response to TRH each identified subgroups of depressed patients. Conversely, blunted TSH response or REM latency were inefficient to classify patients. 4. Thus, HPA hyperactivity characterized CL-I patients (n = 29). These were more severely depressed, displayed more endogenous features and were reported as being more anxious. 5. Increased TSH response to TRH identified CL-III, exclusively composed of female patients (n = 10) that displayed more apparent sadness and tended to be older. 6. In CL-II, the usual sex-ratio for depressive illness was reversed and patients (n = 35) exhibited the least HPA axis disturbances and the same rate of blunted TSH response than in CL-I. They were also less severely depressed, displayed less endogenous characteristics and were rated as more mood reactive. 7. These results suggest heterogeneity in biological disturbances in depression and further stress the importance for controlling age, gender and severity of illness in studies investigating biological markers in depression.
Dept of Psychiatry, Erasme Hospital, Free University of Brussels, Belgium.
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L
Staner
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Linkowski
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J
Mendlewicz
D000328:Adult; D015415:Biomarkers; D016000:Cluster Analysis; D003866:Depressive Disorder / Q000145:classification* / Q000175:diagnosis / Q000523:psychology; D003907:Dexamethasone; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011569:Psychiatric Status Rating Scales; D012895:Sleep, REM / Q000502:physiology; D013973:Thyrotropin-Releasing Hormone
D015415:Biomarkers; D013973:Thyrotropin-Releasing Hormone; D003907:Dexamethasone