Information processing in anxiety: a pilot study of the effect of manipulating 5-HT function.
We gave the indirect 5-HT agonist, D-fenfluramine (30 mg), the 5 -HT antagonist methysergide (2 mg) and placebo to 11 patients with an anxiety disorder and 12 controls in a double-blind, balanced-order, cross-over design. Compared to controls, patients had significantly higher anxiety ratings, were slower in naming colours in computerized Stroop tests and showed greater interference for anxiety-related words. Patients tended to have a lower critical flicker fusion threshold (CFFT) than controls and in the subjects taken as a whole there was a significant inverse correlation between CFFT and Spielberger state (r=-0.54, p<0.01) and trait anxiety (r=-0.55, p<0.01). Neither drug had significant effects on anxiety ratings or on Stroop interference. D-Fenfluramine significantly increased CFFT (p < 0.02) and methysergide non-significantly reduced CFFT with no significant differences between patients and controls. 5-HT may be involved in lower-level visual information processing but we found no evidence for its direct involvement in the attentional bias for anxiety-related information in the emotional Stroop.
Oxford Learning Disability NHS Trust, Headington, UK.
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Andrews
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Anderson
D000328:Adult; D001008:Anxiety Disorders / Q000503:physiopathology*; D001143:Arousal / Q000187:drug effects / Q000502:physiology*; D001288:Attention / Q000187:drug effects / Q000502:physiology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005277:Fenfluramine; D005425:Flicker Fusion / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008784:Methysergide; D008875:Middle Aged; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012684:Sensory Thresholds / Q000187:drug effects / Q000502:physiology; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists
D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D005277:Fenfluramine; D012701:Serotonin; D008784:Methysergide