Effect of acute tryptophan depletion on CO2-induced anxiety in patients with panic disorder and normal volunteers

Uncertainties remain about the role of serotonin in the aetiology and treatment of panic disorder. To investigate the effect of reducing brain serotonin function on anxiety at rest, and following 5% CO2 provocation in normal controls and patients with panic disorder. Twenty drug-free patients with D...

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Bibliographic Details
Published inBritish journal of psychiatry Vol. 176; no. 2; pp. 182 - 188
Main Authors Miller, H. E. J., Deakin, J. F. W., Anderson, I. M.
Format Journal Article
LanguageEnglish
Published Cambridge, UK Cambridge University Press 01.02.2000
RCP
Subjects
Adolescent
Adult
Aged
Amino acids
Analysis of Variance
Antidepressants
Anxiety
Anxiety - chemically induced
Brain serotonin
Carbon dioxide
Carbon Dioxide - administration & dosage
Case-Control Studies
Comorbidity
Depletion
Efficacy
Etiology
Female
Humans
Male
Mental depression
Middle Aged
Panic attacks
Panic Disorder - chemically induced
Panic disorders
Provocation
Psychiatry
Psychological Tests
Resting
Serotonin
Serotonin - deficiency
Serotonin - metabolism
Serotonin - pharmacology
Time Factors
Tryptophan
Variance analysis
Volunteers
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Summary:Uncertainties remain about the role of serotonin in the aetiology and treatment of panic disorder. To investigate the effect of reducing brain serotonin function on anxiety at rest, and following 5% CO2 provocation in normal controls and patients with panic disorder. Twenty drug-free patients with DSM-III-R panic disorder and 19 controls received a tryptophan-free amino acid drink on one occasion and a control drink on the other in a double-blind, balanced protocol. 5% CO2 was given as a panic challenge after 270 minutes. Plasma tryptophan fell by more than 80% both patients and controls after the tryptophan-free drink. Tryptophan depletion did not alter resting anxiety. In patients alone, tryptophan depletion caused a greater anxiogenic response and an increased rate of panic attacks (9 v. 2, P < 0.05) after 5% CO2 challenge. No normal volunteers panicked. Serotonin may directly modulate panic anxiety in patients with panic disorder. This may underlie the efficacy of serotonergic antidepressants in treating panic disorder.
ISSN:0007-1250
1472-1465
DOI:10.1192/bjp.176.2.182