Testosterone levels and discounting delayed monetary gains and losses in male humans.

OBJECTIVES: Although impulsivity has been associated with androgens (e.g., testosterone), little is known regarding the relationship between testosterone levels and impulsivity in intertemporal choice (delay discounting). This study was aimed to examine the relationship between delay discounting of gains and losses and testosterone levels, which is of interest in neuroendocrinology and neuroeconomics.

METHODS: We assessed degrees to which delayed monetary gains and losses were discounted (hyperbolic discounting rate) in healty male students (age: 22.4+/-2.67). Participants' salivary testosterone levels were also assessed by utilizing liquid chromatography/mass spectroscopy (LC/MS) method.

RESULTS: Non-linear curve fitting analysis showed an inverted-U relationship between delay discounting of gains and salivary testosterone levels; while no relationship between salivary testosterone levels and delay discounting of losses was observed.

CONCLUSIONS: The results indicate that (i) testosterone may enhance delay discounting rate of gains in non-impulsive subjects, (ii) testosterone may have an opposite (reducing) effect on delay discounting rate of gains in impulsive subjects, and (iii) testosterone is unrelated to subject's sensitivity to future bad outcomes. Implications for evaluating the effects of testosterone treatment and anti-androgenic therapy on impulsive behavior often observed in psychiatrics (e.g., pathological gambling, credit card debt, substance misuse, and needle-sharing) are discussed.