All subjects gave written informed consent for their participation in a protocol approved by the Washington University School of Medicine Human Studies Committee, St Louis, Mo. Subjects aged 18 to 30 years were recruited using local advertisements and were screened for general medical health, including psychiatric disorders, using the Diagnostic Interview for Genetic Studies.49 Subjects were excluded for the presence of clinically significant medical or psychiatric disease, including (1) type 1 or 2 diabetes mellitus, hypertension, any major surgery within the previous 6 months, any cardiac condition causing documented hemodynamic compromise, any respiratory condition causing documented or clinically recognized hypoxia, fever, dehydration, nausea, epilepsy, other endocrine disease, body weight less than 80% ideal body weight, any other medical condition requiring more than 7 days of hospitalization in the past 4 weeks, pregnancy or higher-dose estrogen therapy, narcotic therapy, corticosteroid or spironolactone therapy, and psychotropic therapy; (2) any Axis I psychiatric disorder, including any substance use disorders; and (3) mental retardation as determined by DSM-IV criteria. Twenty-five men and 26 women were assigned to the higher-dose cortisol (7 men and 8 women), lower-dose cortisol (8 men and 8 women), and placebo (10 men and 10 women) groups. Complete data were available for most of the cognitive analyses for all 51 subjects, with complete plasma data for 50 of them at baseline and 49 of them over all sampling times. Clinical characteristics of the sample were as follows (mean±SD): age, 22.2±2.8 years; body mass index (calculated as weight in kilograms divided by the square of the height in meters, 23.0±3.9; and education, 15.5±1.96 years. No significant differences across treatment groups were detected for age (F2,48=0.003; P=.99); body mass index (F2,48=1.03; P=.36); education (F2,48=0.49; P=.61); Wechsler Adult Intelligence Scale–Revised information (F2,48=0.65; P=.53), vocabulary (F2,48=0.75; P=.48) and block design (F2,47=0.33; P=.72) subscale scores; handedness (F2,47=0.66; P=.52); or baseline cortisol (F2,47=1.30; P=.28), insulin (F2,47=0.007; P=.99), or glucose (F2,47=0.04; P=.96) plasma concentrations.