Impact of acute tryptophan depletion on mood and eating-related urges in bulimic and nonbulimic women

Impact of acute tryptophan depletion on mood and eating-related urges in bulimic and nonbulimic women

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J Psychiatry Neurosci 2009; 34(5): 376-382

Kenneth R. Bruce, PhD; Howard Steiger, PhD; Simon N. Young, PhD; N.M.K. Ng Ying Kin, PhD; Mimi Israël, MD; Mélissa Lévesque, BA

Bruce, Steiger, Israël, Lévesque — Eating Disorders Program, Douglas Institute; Bruce, Steiger, Kin, Israël — Research Centre, Douglas Institute; Bruce, Steiger, Young, Kin, Israël, Lévesque — Department of Psychiatry, McGill University, Montréal, Que.

Abstract

Background: Previous research has shown that many people experience a temporary worsening of mood following acute tryptophan depletion (ATD) and that concurrent use of serotonergic medications may influence such mood responses. We investigated mood and other consequences of ATD in women with bulimia nervosa who were or were not using concurrent serotonergic medications compared with women without bulimia.

Methods: Women self-referred for treatment of bulimia who were either not currently using psychoactive medications (n = 26) or who were using serotonin reuptake inhibitor medications exclusively (n = 13), as well as medication-free normaleater control women (n = 25) completed interviews and questionnaires assessing eating and comorbid psychopathology and then participated in an ATD procedure involving balanced and tryptophan-depleted conditions.

Results: In the tryptophan-depleted condition, the groups displayed similar and significant decrements in plasma tryptophan levels and mood. Women with bulimia who were using serotonin reuptake inhibitors, but not the other groups, also reported an increased urge to binge eat in the tryptophan-depleted condition.

Limitations: Application of medication in participants with bulimia was not random.

Conclusions: Acute reductions in serotonin availability produced similar mood-reducing effects in bulimic and nonbulimic women. To the extent that ATD affected subjective experiences pertinent to eating (i.e., urge to binge eat), such effects appeared to depend upon ATD-induced competition with the therapeutic effects
of serotonergic medications.


Submitted Dec. 8, 2008; Revised Apr. 16, Jun. 1, 2009; Accepted Jun. 2, 2009.

Acknowledgements: This research was supported by grants from the Canadian Institutes for Health Research (No. MOP-57929 awarded to H.S.) and the Fonds pour la recherche en santé du Québec (No. 24100-1745 awarded to K.R.B.). We thank Jodie Richardson, Cathy Dandurand, Annélie Annestin and Sarah Racine for their contributions to data collection and preparation.

Competing interests: None declared.

Contributors: Drs. Bruce, Steiger, Young and Israël designed the study. Drs. Bruce, Steiger, Kin, Israël and Ms. Lévesque acquired the data, which all authors analyzed. Drs. Bruce and Steiger wrote the article, which all authors reviewed. All authors approved final publication.

Correspondence to: Dr. K.R. Bruce, Eating Disorders Program, Douglas Institute, 6875 LaSalle Blvd., Montréal QC H4H 1R3; bruken@douglas.mcgill.ca