Studying the effects of dietary body weight-adjusted acute tryptophan depletion on punishment-related behavioral inhibition

Tilman J. Gaber; Vita L.S. Dingerkus; Molly J. Crockett; Sarah Bubenzer-Busch; Katrin Helmbold; Cristina L. Sánchez; Brigitte Dahmen; Beate Herpertz-Dahlmann; Florian D. Zepf

doi:10.3402/fnr.v59.28443

Tilman J. Gaber Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen/Germany
Vita L.S. Dingerkus Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen/Germany
Molly J. Crockett Wellcome Trust Centre for Neuroimaging, University College London, United Kingdom
Sarah Bubenzer-Busch Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen/Germany
Katrin Helmbold Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen/Germany
Cristina L. Sánchez Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen/Germany
Brigitte Dahmen Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen/Germany
Beate Herpertz-Dahlmann Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen/Germany
Florian D. Zepf Department of Child and Adolescent Psychiatry, The University of Western Australia (UWA), Perth, Australia

DOI: https://doi.org/10.3402/fnr.v59.28443

Abstract

Background: Alterations in serotonergic (5-HT) neurotransmission are thought to play a decisive role in affective disorders and impulse control.

Objective: This study aims to reproduce and extend previous findings on the effects of acute tryptophan depletion (ATD) and subsequently diminished central 5-HT synthesis in a reinforced categorization task using a refined body weight–adjusted depletion protocol.

Design: Twenty-four young healthy adults (12 females, mean age [SD]=25.3 [2.1] years) were subjected to a double-blind within-subject crossover design. Each subject was administered both an ATD challenge and a balanced amino acid load (BAL) in two separate sessions in randomized order. Punishment-related behavioral inhibition was assessed using a forced choice go/no-go task that incorporated a variable payoff schedule.

Results: Administration of ATD resulted in significant reductions in TRP measured in peripheral blood samples, indicating reductions of TRP influx across the blood–brain barrier and related brain 5-HT synthesis. Overall accuracy and response time performance were improved after ATD administration. The ability to adjust behavioral responses to aversive outcome magnitudes and behavioral adjustments following error contingent punishment remained intact after decreased brain 5-HT synthesis. A previously observed dissociation effect of ATD on punishment-induced inhibition was not observed.

Conclusions: Our results suggest that neurodietary challenges with ATD Moja–De have no detrimental effects on task performance and punishment-related inhibition in healthy adults.

Keywords: acute tryptophan depletion; serotonin; executive functions; decision-making; gender

(Published: 11 August 2015)

Citation: Food & Nutrition Research 2015, 59: 28443 - http://dx.doi.org/10.3402/fnr.v59.28443

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Author Biography

Florian D. Zepf, Department of Child and Adolescent Psychiatry, The University of Western Australia (UWA), Perth, Australia

Prof. Dr. Florian D. Zepf is the Chair and Winthrop Professor of Child and Adolescent Psychiatry at the University of Western Australia, and the Clinical Director / Head of Department of the Specialised Child and Adolescent Mental Health Services in Western Australia.

He is the recipient of prestigious research awards, including the "Young Minds in Psychiatry Award" (awarded by the American Psychiatric Association and the American Psychiatric Institute for Research and Education), the Donald J. Cohen Fellowship Award (granted by the International Association of Child and Adolescent Psychiatry and Allied Professions) and the Raine Visiting Professorship of the University of Western Australia.

He has published several papers and book chapters on a variety of topics related to different aspects of mental health in children and adolescents, and is an internationally highly recognized clinician and researcher in the field of paediatric neuropsychopharmacology. His main research interests are neurochemical aspects of brain function and their development in neuropsychiatric disorders, neuroimaging, neurofeedback, eating disorders as well as attention and affective disorders.

He is a member of the American Academy of Child and Adolescent Psychiatry (AACAP), the American Psychiatric Association (APA), the German Society of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy (DGKJP), the Society of Biological Psychiatry (SOBP), the International College of Neuropsychopharmacology (CINP), the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP), the International Society fo Serotonin Research, and the International Society for Tryptophan Research (ISTRY).