Sensitivity and Specificity of Coupled Dexamethasone Suppression and TRH Infusion Tests in 90 Postsuicide Hospitalized Adolescents with Depression

In order to reduce the possible confounding effect of suicidality on studies of biological markers in adolescents, we examined a sample consisting solely of adolescents hospitalized following a suicide attempt. Of 112 adolescents hospitalized after a suicide attempt, 90 met DSM-III-R criteria for a depressive disorder: major depression presented in 54% of these cases, dysthymia in 11%, and both (double depression) in 35%. The 22 adolescents who did not have depression formed the psychiatric control group. All patients were administered a dexamethasone suppression test and a TRH infusion test after several days in the hospital. There were no significant differences in DST or TRH responses among the adolescents with major depression, dysthymic disorder, or double depression. Among the depressed adolescents, cortisol nonsuppression was found in 42%, and blunted TSH response was noted in 51%; one of the two tests was abnormal in 74% of the depressed adolescents, and both tests were abnormal in 19%. Among the nondepressed adolescents, 18% manifested cortisol nonsuppression (a result which differs from the depressed group, p < 0.05) and 14% showed blunted TSH response (p < 0.01); one of the two tests was abnormal in 27% of the nondepressed adolescents (p < 0.0001), and both tests were abnormal in only one nondepressed patient (NS). For identifying depressed adolescents, the DST had a sensitivity of 42% and a specificity of 82%. The TRH test had a sensitivity of 51% and a specificity of 86%. An abnormality on one of the two tests had a sensitivity of 74% and a specificity of 73%. The sensitivity of the coupled tests was 19%, and the specificity was 95%. These figures do not provide a basis to support the use of these tests, singly or coupled, as a major clinical aid in the identification of depressed adolescents, even among postsuicide depressed adolescents.