The relationships between relative hypo- and hypercortisolism and depression as well as low global functioning and quality of life in bipolar disorder.

BAI, Beck Anxiety Inventory; BSA-S, Brief Scale for Anxiety – Self assessment; BDI, Beck Depression Inventory; BMI, body mass index; CI, 95% confidence interval; DST, dexamethasone suppression test; GAF, Global Assessment of Functioning; MADRS-S, Montgomery Åsberg Depression Rating Scale – Self assessment; OR, odds ratio; QOL, Quality of Life.
The table describes the OR:s of the high or low post-DST groups as compared to the mid-group (the reference group) for exhibiting depression, anxiety, low quality of life and low global functioning. The logistic regression analyses were performed unadjusted and in a model adjusting for age, sex and diagnosis (bipolar type 1 or 2). The outcome variables of the logistic regression analyses were the questionnaire scores dichotomized according to established cut-offs when present (BDI, MADRS-S, BAI, See the statistical methods paragraph). The remaining questionnaire scores (BSA-S, GAF WHOQOL-100) which lacked established cut-offs were dichotomized comparing the lowest quartile with the rest. We also tested for additional potential confounding through individually including within the model the following variables: BMI, smoking, antidepressant medication, neuroleptic medication, sedative medication and medication with mood stabilizer (see statistical section). Significant adjusted analyses remained significant also after these additional potential confounders were added to the model except for one instance when BMI was added to the high vs. mid analyses with respect to MADRS-S where the cortisol group variable showed a trend toward significance (p = 0.054).
aPost-DST cortisol groups were formed by using the 25th and 75th percentiles among the controls as cut-offs to divide both controls and patients into 3 groups. A low post DST cortisol value (subjects below the 25th percentile) was used to identify subjects exhibiting relative hypocortisolism and a high post DST cortisol value (subjects above the 75th percentile) was used to identify subjects exhibiting relative hypercortisolism. Subjects showing post DST cortisol values between the 25th and 75th percentiles were identified as subjects exhibiting eucortisolism.
bAdjusted for sex, age and diagnosis (bipolar type 1 or 2).
cIn the GAF analyses n were as follows: low vs. mid cortisol group, n = 96; high vs. mid cortisol group, n = 105; low and high vs. mid cortisol group, n = 142.
dIn the Quality of Life analyses n were as follows: low vs. mid cortisol group, n = 96; high vs. mid cortisol group, n = 108; low and high vs. mid cortisol group, n = 144.