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Journal Article 2011; 32(6): 836-840 PubMed PMID: 22286788 Citation  Keywords:  Adolescent, Female, Humans, Impulsive Behavior:metabolism, Loneliness, Neuropsychological Tests, Saliva:chemistry, Testosterone:metabolism,.   

OBJECTIVE: Adolescence is characterized by increases in loneliness, impulsiveness and circulating testosterone levels. We investigated the relationship between these characteristics in adolescent females.

METHODS: For this purpose, we measured impulsivity and loneliness by means of a Go/No-go task and the UCLA loneliness scale, respectively. Testosterone levels in saliva were measured by Enzyme-Linked Immunosorbent Assay (ELISA).

RESULTS: The results showed that testosterone and loneliness have a positive relevance to impulsivity in adolescent females, whereas there was no relationship between loneliness and testosterone levels.

CONCLUSIONS: These results suggest that testosterone and loneliness modulate impulsivity via distinctive pathways....

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Comparative Study 2010; 31(5): 616-621 PubMed PMID: 21178944 Citation  Keywords:  Adult, Aged, Choice Behavior, Corticosterone:secretion, Female, Follow-Up Studies, Humans, Hydrocortisone:secretion, Impulsive Behavior:metabolism, Individuality, Male, Mass Spectrometry, Middle Aged, Models, Psychological, Reward, Saliva:metabolism, Sex .   

OBJECTIVES: Stress hormones have been associated with temporal discounting. Although time-discount rate is shown to be stable over a long term, no study to date examines whether individual differences in stress hormones could predict individuals' time-discount rates in the relatively distant future (e.g., six month later), which is of interest in neuroeconomics of stress-addiction association.

METHODS: We assessed 87 participants' salivary stress hormone (cortisol, cortisone, and alpha-amylase) levels and hyperbolic discounting of delayed rewards consisting of three magnitudes, at the time-interval of six months. For salivary steroid assays, we employed a liquid chromatography/ mass spectroscopy (LC/MS) method. The correlations between the stress hormone levels and time-discount rates were examined.

RESULTS: We observed that salivary alpha-amylase (sAA) levels were negatively associated with time-discount rates in never-smokers. Notably, salivary levels of stress steroids (i.e., cortisol and cortisone) negatively and positively related to time-discount rates in men and women, respectively, in never-smokers. Ever-smokers' discount rates were not predicted from these stress hormone levels.

CONCLUSIONS: Individual differences in stress hormone levels predict impulsivity in temporal discounting in the future. There are sex differences in the effect of stress steroids on temporal discounting; while there was no sex defference in the relationship between sAA and temporal discounting....

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Clinical Trial 2007; 28(1): 17-20 PubMed PMID: 17277731 Citation  Keywords:  Adolescent, Adrenal Medulla:physiology, Adult, Choice Behavior:physiology, Humans, Impulsive Behavior:metabolism, Male, Saliva:chemistry, Sympathetic Nervous System:physiology, Testosterone:metabolism, alpha-Amylases:analysis,.   

OBJECTIVE: Little is known regarding the role of the sympathetic-adrenal-medullary (SAM) system in self-control and impulsivity in intertemporal choice (delay discounting), although the roles of dopaminergic and serotonergic systems have been extensively examined. This study was aimed to examine the relationships between salivary alpha-amylase (sAA, a non-invasive biological marker of adrenergic/SAM activities) levels and hyperbolic discounting, which is of interest in psychoneuroendocrinology and neuroeconomics.

METHODS: We assessed degrees to which delayed monetary gains were discounted (hyperbolic discount rates) in healthy male students. Participants' sAA were also assessed.

RESULTS: We observed negative relationships between sAA and hyperbolic discounting of small, medium, and large monetary gains.

CONCLUSIONS: The results indicate that subjects with low sAA are impulsive in intertemporal choice. Implications for the roles of adrenergic and SAM systems in self-control in intertemporal choice are discussed....

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Journal Article 2006; 27(4): 439-444 PubMed PMID: 16891992 Citation  Keywords:  Adult, Choice Behavior:physiology, Decision Making:physiology, Economics, Humans, Impulsive Behavior:metabolism, Male, Nonlinear Dynamics, Risk-Taking, Saliva:metabolism, Surveys and Questionnaires, Testosterone:metabolism, Time Factors,.   

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....

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