RationaleAcute stress produces behavioral and physiological changes modulated by central catecholamines (CA). Stress increases CA activity, and depletion of CA stores reduces responses to stress. Increasing CA activity by administration of the dietary amino acid CA precursor tyrosine may increase responsiveness to stress. This study determined whether tyrosine enhances the ability of humans to respond to severe stress.MethodsSevere psychological stress was generated during training at Survival, Evasion, Resistance, and Escape (SERE) School. The acute stressor consisted of two mock interrogations conducted during several days of simulated captivity. Seventy-eight healthy male and female military personnel participated in this double-blind, between-subjects study, in which they received either tyrosine (300 mg/kg, N = 36) or placebo (N = 36). Tyrosine (or placebo) was administered in food bars in two doses of 150 mg/kg each approximately 60 min before each mock interrogation. Mood (Profile of Mood States), saliva cortisol, and heart rate (HR) were assessed prior to stress exposure during a week of academic training preceding mock captivity and immediately following the mock interrogations.ResultsThe severe stress produced robust effects on mood (i.e., increased tension, depression, anger, fatigue, vigor, and confusion; p < .001), cortisol, and HR (p < .001). Tyrosine increased anger (p = .002, ANOVA treatment condition by test session interaction) during stress but had no other effects.ConclusionTyrosine did not alter most subjective or physiological responses to severe acute stress, but it increased ratings of anger. The modest increase in anger may be an adaptive emotional response in stressful environments.
Results of past empirical studies utilizing the Minnesota Multiphasic Personality Inventory (MMPI) and the Rorschach Inkblot Test (Rorschach) have tended to be equivocal regarding the level and nature of psychopathology associated with samples of individuals requesting gender reassignment surgery. The present study compared the MMPI-2 basic scale T scores from a gender reassignment applicant sample (56 male-to-female transsexuals and 56 female-to-male transsexuals) to T scores obtained from a general psychiatric adult inpatient sample (n = 112) and T scores obtained from a normal adult sample (n = 112). The comparison groups were matched to the gender reassignment sample on the variables of biological gender and age. Rorschach data obtained from the gender reassignment sample were also compared to frequency data reported by Exner for normal, character disorder, and schizophrenic adults. Apart from a clinical range elevation on Scale 5, the gender reassignment candidates produced a normal range mean MMPI-2 profile. In contrast, the Rorschach findings suggested that reassignment candidates produce a high frequency of invalid protocols and manifest various psychological problems that are characteristic of individuals with personality disorders. These findings are discussed in terms of salient methodological and theoretical issues as well as promising directions for future research.
A method for assessing the relative sensitivity of research metrics is proposed and illustrated by comparing 18 outcome measures from a published study of the cognitive, mood, and hormonal effects of four different levels of stress induced by intense military training. Research on the human response to stress often assesses multiple disparate dependent measures. Selecting the most sensitive is difficult as formal methods to compare varied dependent measures have not been developed. The method first converts the outcome measures into standard scores (z‐scores) and then compares them using analysis of variance to determine whether there are differences in how they assess the impact of graded levels of exposure to stress. The analysis detected various significant interactions in several measures and suggests self‐report mood questionnaires were more sensitive to the stressors present in the study than the cognitive or hormonal measures which were used. These findings support the effectiveness of the z‐score based method as a useful procedure for objectively evaluating the differential sensitivity of various metrics. This method could be useful for research on other independent variables when use of multiple assessment strategies is appropriate. It could be used for evaluating studies yielding conflicting results, such as those detecting effects on one parameter but not others. In such instances, cross‐metric inconsistencies may be due to differential sensitivity of measurement strategies rather than actual differences in the effects of the independent‐variable on the domains under investigation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.