The effects of caffeine on plasma MHPG, subjective anxiety, autonomic symptoms and blood pressure in healthy humans

Life Sci. 1984 Jul 9;35(2):135-44. doi: 10.1016/0024-3205(84)90132-2.


The effects of oral administration of caffeine (10 mg/kg) on plasma free 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) levels, behavioral ratings, blood pressure, and autonomic symptoms was determined in eleven healthy subjects. Caffeine produced robust increases in subject rated anxiety and nervousness and small elevations in blood pressure and a decrease in heart rate. Caffeine did not alter plasma MHPG in a consistent fashion and there was no correlation between changes in plasma MHPG and changes in anxiety or other ratings. Caffeine may produce symptoms of anxiety-nervousness without increasing central norepinephrine turnover.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Anxiety / drug effects*
  • Autonomic Nervous System / drug effects*
  • Behavior / drug effects
  • Blood Pressure / drug effects*
  • Caffeine / blood
  • Caffeine / pharmacology*
  • Female
  • Glycols / blood*
  • Heart Rate / drug effects
  • Humans
  • Male
  • Methoxyhydroxyphenylglycol / blood*
  • Middle Aged
  • Posture
  • Time Factors
  • Wakefulness / drug effects


  • Glycols
  • Caffeine
  • Methoxyhydroxyphenylglycol