The effect of 5-hydroxytryptophan on cholecystokinin-4-induced panic attacks in healthy volunteers

J Psychopharmacol. 2004 Jun;18(2):194-9. doi: 10.1177/0269881104042619.


Previous studies suggest a modulatory role of serotonin (5-HT) in experimentally-induced panic attacks. In the current study, we investigated the acute effects of 5-HT precursor l-5-hydroxytryptophan (5-HTP) on the response to panicogenic challenge with cholecystokinin-tetrapeptide (CCK-4) in healthy volunteers. Thirty-two subjects were randomized to receive either 200 mg of 5-HTP or placebo with the CCK-4 challenge following in 90 min in a double-blind, parallel-group design. The results showed a nonsignificant difference between the groups in panic rate (19% after 5-HTP and 44% after placebo, p = 0.13) with a trend for lower intensity of symptoms after 5-HTP (p = 0.08). Further analysis by gender revealed that females in the 5-HTP group had a significantly lower panic rate and intensity of cognitive symptoms whereas, in males, the effect of 5-HTP was limited to lowering the intensity of somatic panic symptoms. Thus, an increased availability of 5-HT may have a gender-dependent protective effect in CCK-4-induced panic.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-Hydroxytryptophan / administration & dosage
  • 5-Hydroxytryptophan / pharmacokinetics
  • 5-Hydroxytryptophan / therapeutic use*
  • Administration, Oral
  • Adolescent
  • Adult
  • Capsules
  • Cognition Disorders / chemically induced
  • Cognition Disorders / drug therapy
  • Cognition Disorders / prevention & control
  • Double-Blind Method
  • Female
  • Humans
  • Hypertension / chemically induced
  • Injections, Intravenous
  • Male
  • Panic Disorder / chemically induced*
  • Panic Disorder / drug therapy
  • Panic Disorder / prevention & control*
  • Psychiatric Status Rating Scales
  • Sex Characteristics
  • Tachycardia / chemically induced
  • Tetragastrin / administration & dosage
  • Tetragastrin / adverse effects*
  • Tetragastrin / pharmacokinetics
  • Time Factors


  • Capsules
  • Tetragastrin
  • 5-Hydroxytryptophan