The catecholamine neurotransmitter precursor tyrosine increases anger during exposure to severe psychological stress

source extracted confidence: high 2026-04-09
#adult #affect #anger #double-blind-method #female

The catecholamine neurotransmitter precursor tyrosine increases anger during exposure to severe psychological stress

Lieberman et al., 2015 | Psychopharmacology (Berl) | Rct

Citation

Lieberman Harris R, Thompson Lauren A, ... Caron Gregory R. The catecholamine neurotransmitter precursor tyrosine increases anger during exposure to severe psychological stress. Psychopharmacology (Berl). 2015-Mar;232(5):943-51. doi:10.1007/s00213-014-3727-7

Abstract

RATIONALE: Acute 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. METHODS: Severe 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. RESULTS: The 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. CONCLUSION: Tyrosine 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.

Key Findings

The 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.

Outcomes Measured

  • depression
  • cortisol levels

Population

Field Value
Population See abstract
Sample Size 36
Age Range See abstract
Condition depression

MeSH Terms

  • Adult
  • Affect
  • Anger
  • Double-Blind Method
  • Female
  • Heart Rate
  • Humans
  • Hydrocortisone
  • Male
  • Saliva
  • Stress, Psychological
  • Tyrosine
  • Young Adult

Evidence Classification

  • Level: Rct
  • Publication Types: Journal Article, Randomized Controlled Trial, Research Support, U.S. Gov't, Non-P.H.S.
  • Vertical: tyrosine

Provenance

Source extracted via PubMed E-utilities API on 2026-04-10