Investigating the neural basis of the effect of an acute tryptophan challenge and a tryptophan-enriched diet on social cognition

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

DRKS

Registry ID

DRKS00010677

Enrollment

Registered

2016-07-25

Start date

2016-09-01

Completion date

Unknown

Last updated

2025-04-07

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

healthy participants

Interventions

Group 1: 5-HTP (Hydroxytryptophan), once 200mg, vegan capsule to take with a glass of fluid Group 2: placebo, once Group 3: L-Tryptophan, 500mg in cereal bar, 5x/week over 4 weeks Group 4: Placebo in

Eligibility

Sex/Gender

All

Age

21 Years to 65 Years

Inclusion criteria

Inclusion criteria: MRI ok, no mental disorders, BMI between 18 and 30

Exclusion criteria

Exclusion criteria: no MRI possible, mental disorders, BMI 30

Design outcomes

Primary

Measure	Time frame
Improvement of social cognition with TRP (Tryptophan) fMRI, several paradigms on social cognition and emotion recognition (RMET, Hariri matching task, moral judgement task acc. to Young et al) and questionnaires (BDI II, STAI, Leids, EQ, WHO5, PTQ, questionaire on TRP rich nutrition, GPAQ, SI, PSQI, FSS, social network and activity) of 3 time points: baseline, after 5-HTP (2h after application MRI measurement and questionaires) and after L-Tryptophan (after 4 weeks, max. 1 week after last intake MRI and questionaires) 2 time points: urine for measurement of TRP metabolites and blood to find associations to TRP genetics and epigenetic factors 80 participants	—

Measure

Time frame

Improvement of social cognition with TRP (Tryptophan) fMRI, several paradigms on social cognition and emotion recognition (RMET, Hariri matching task, moral judgement task acc. to Young et al) and questionnaires (BDI II, STAI, Leids, EQ, WHO5, PTQ, questionaire on TRP rich nutrition, GPAQ, SI, PSQI, FSS, social network and activity) of 3 time points: baseline, after 5-HTP (2h after application MRI measurement and questionaires) and after L-Tryptophan (after 4 weeks, max. 1 week after last intake MRI and questionaires) 2 time points: urine for measurement of TRP metabolites and blood to find associations to TRP genetics and epigenetic factors 80 participants

—

Secondary

Measure	Time frame
Well being/life satisfaction (e.g. WHO5) sleep quality (PSQI); prior to and after intake of Tryptophan	—

Countries

Germany

Contacts

Public ContactVera Zamoscik

Zentralinstitut für Seelische Gesundheit Mannheim

vera.zamoscik@zi-mannheim.de0621/1703-6162

Outcome results

None listed

Source: DRKS (via WHO ICTRP) · Data processed: Feb 4, 2026