Endogenous testosterone levels are associated with assessments of unfavourable health information.

The purpose of this study was to investigate whether participants' assessments of unfavourable health information are associated with individual differences in basal testosterone. Testosterone has previously been related to assessments of threat in social and other domains. 52 undergraduate males were tested for a minor, fictitious medical condition thioamine acetylase deficiency ('TAA deficiency') in a paradigm that was developed to examine the thoughts and behaviours of individuals who have just received unfavourable medical news. In a variation on the classic paradigm, all participants were told that they had 'TAA deficiency,' after which they rated the seriousness and prevalence of that condition as well as 19 other actual conditions. Higher testosterone levels were significantly correlated with lower estimates of both the seriousness and prevalence of TAA deficiency as well as lower median seriousness and prevalence estimates of the 19 actual conditions. Findings are discussed in light of current research in the field of behavioural endocrinology. This study provides preliminary evidence that individual differences in assessments of threatening health information may be associated with neurobiological characteristics.

Testosterone is positively associated with risk taking in the Iowa Gambling Task.

The association between testosterone and economic risk is not well-understood and is understudied. The present study aimed to further characterize what if any relationship testosterone has with risky economic decisions. To do so, 154 participants (78 men) completed the Iowa Gambling Task (IGT) (Bechara et al., 1994) and also provided saliva samples, which were assayed for endogenous testosterone levels using radioimmunoassay. High-levels of endogenous testosterone were associated with choosing less frequently from advantageous IGT decks of cards, indicating greater risk taking. The data showed that the effects of testosterone on IGT performance were similar for men and women. High-testosterone women and high-testosterone men made riskier choices than their low-testosterone counterparts of the same sex, and this effect was pronounced in women. Thus, high levels of testosterone are associated with willingness to incur greater risk in both sexes.

Salivary testosterone, cortisol, and progesterone: two-week stability, interhormone correlations, and effects of time of day, menstrual cycle, and oral contraceptive use on steroid hormone levels.

With salivary assessment of steroid hormones increasing, more work is needed to address fundamental properties of steroid hormone levels in humans. Using a test-retest design and radioimmunoassay assessment of salivary steroids, we tested the reliability of testosterone, cortisol, and progesterone levels across two weeks, as well as the effects of oral contraceptives, menstrual cycle phase, and time of day on steroid hormone levels. Testosterone and cortisol were found to be highly reliable in both sexes. Progesterone was found to be reliable after collapsing across sex. Oral contraceptive use was associated with lower levels of testosterone, but did not affect cortisol. Contrary to expectations, oral contraceptives also did not affect progesterone. Menstrual cycle was found to affect levels of progesterone, but not testosterone or cortisol. Time of day had an effect on cortisol, on progesterone only at one testing time, and no effect on testosterone. We explored the interhormone correlations among testosterone, progesterone, and cortisol. All three hormones were positively correlated with one another in men. In women, progesterone was positively correlated with testosterone and cortisol, but testosterone and cortisol were uncorrelated.