The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans.
L-Theanine (delta-glutamylethylamide) is one of the predominant amino acids ordinarily found in green tea, and historically has been used as a relaxing agent. The current study examined the acute effects of L-theanine in comparison with a standard benzodiazepine anxiolytic, alprazolam and placebo on behavioural measures of anxiety in healthy human subjects using the model of anticipatory anxiety (AA). Sixteen healthy volunteers received alprazolam (1 mg), L-theanine (200 mg) or placebo in a double-blind placebo-controlled repeated measures design. The acute effects of alprazolam and L-theanine were assessed under a relaxed and experimentally induced anxiety condition. Subjective self-reports of anxiety including BAI, VAMS, STAI state anxiety, were obtained during both task conditions at pre- and post-drug administrations. The results showed some evidence for relaxing effects of L-theanine during the baseline condition on the tranquil-troubled subscale of the VAMS. Alprazolam did not exert any anxiolytic effects in comparison with the placebo on any of the measures during the relaxed state. Neither L-theanine nor alprazalam had any significant anxiolytic effects during the experimentally induced anxiety state. The findings suggest that while L-theanine may have some relaxing effects under resting conditions, neither L-theanine not alprazolam demonstrate any acute anxiolytic effects under conditions of increased anxiety in the AA model.
Lu
Kristy
K
Neuropsychopharmacology Laboratory, Brain Sciences Institute, Swinburne, University of Technology, Victoria, Australia.
Gray
Marcus A
MA
Oliver
Chris
C
Liley
David T
DT
Harrison
Ben J
BJ
Bartholomeusz
Cali F
CF
Phan
K Luan
KL
Nathan
Pradeep J
PJ
D000328:Adult; D000525:Alprazolam / Q000627:therapeutic use*; D014151:Anti-Anxiety Agents / Q000627:therapeutic use*; D001007:Anxiety / Q000188:drug therapy*; D004311:Double-Blind Method; D005260:Female; D005971:Glutamates / Q000627:therapeutic use*; D006801:Humans; D008297:Male
D014151:Anti-Anxiety Agents; D005971:Glutamates; C026166:theanine; D000525:Alprazolam