Cognitive therapy does not prevent a response to tryptophan depletion in patients also treated with antidepressants

Biol Psychiatry. 2005 Dec 1;58(11):913-5. doi: 10.1016/j.biopsych.2005.04.054. Epub 2005 Jul 22.


Background: Acute tryptophan depletion (ATD) induces depressive symptoms in remitted depressed patients treated with serotonergic medications, but not in patients treated with noradrenergic medications or electroconvulsive therapy. A recent study suggests that cognitive therapy (CT) protects against the effects of ATD, but the evidence is questionable. The present study compared the effect of ATD in patients who were treated with antidepressant medication and CT (n = 17) versus antidepressant medication alone (n = 23) during their latest episode.

Methods: Forty remitted depressed patients underwent high-dose and low-dose ATD in a randomized double-blind crossover design.

Results: There were no differences in response to ATD between treatment groups. This applied to groups defined by lifetime and by recent CT experience.

Conclusions: Cognitive therapy does not protect against the effects of rapidly lowered plasma tryptophan levels in remitted depressed patients who are also treated with antidepressant medication.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Antidepressive Agents / administration & dosage
  • Antidepressive Agents / therapeutic use*
  • Behavior
  • Cognitive Behavioral Therapy*
  • Combined Modality Therapy
  • Depressive Disorder / drug therapy
  • Depressive Disorder / psychology
  • Depressive Disorder / therapy*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Psychiatric Status Rating Scales
  • Tryptophan / deficiency*


  • Antidepressive Agents
  • Tryptophan