Serotonin and Everyday Social Interaction

Everyday Social Behavior and Mood in Individuals With a Family History of Depression. Investigating the Role of Serotonin

Rationale: Poor social functioning may contribute to major depressive disorder (MDD). Poor serotonin function may also contribute to MDD. Recent research suggests that serotonin plays a role in regulating human social behaviour. Therefore it would be intriguing to investigate the role of serotonin in regulating the quality of everyday social interactions in a population at risk for MDD. Human social behaviour can be reliably assessed in everyday life using Ecological Momentary Assessment (EMA).

Objective: This study aims to investigate how an experimental increase in serotonin influences social functioning in healthy adults with a first-degree family member diagnosed with MDD. The primary goal is to investigate the role of serotonin in regulating everyday social behaviour, measured using EMA. This will be done using oral supplementation with tryptophan, the amino acid precursor of serotonin. Secondary goals are to determine how this experimental manipulation influences people's feelings as well as their perceptions of other's social behaviour following interpersonal events, and social cognitions at the end of the day. An exploratory goal is to investigate if these effects are moderated by genes thought to be involved in MDD.

The primary hypothesis to be tested is that tryptophan will reduce quarrelsome behaviour.

Study Overview

• Status: Completed
• Conditions: Social Behaviour
• Intervention / Treatment: Dietary supplement: Tryptophan

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Early Phase 1

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 18-65 years
• At least one first-degree family member with MDD
• Willingness to cooperate; to sign written informed consent

Exclusion Criteria:

• Any current or past MDD or other mood disorder as determined by the Structured Clinical Interview for the Diagnostic and Statistical Manual for Mental Disorders (SCID)
• Any current anxiety disorder, psychotic disorder, substance use disorder, eating disorder, or somatoform disorder as determined by SCID
• Any contraindication for the use of tryptophan, i.e. pregnancy, diabetes, cancer or a history of cancer, a history of any scleroderma-like condition, evidence of achlorhydria, upper bowel malabsorption, or irritation of the urinary bladder
• Current use of psychotropic medications including medications for psychiatric problems (e.g., antidepressants such as Mono Amine Oxidase inhibitors and fluoxetine) or migraines
• Not speaking Dutch fluently

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Tryptophan first; Tryptophan is given for the first 14 days, 6 times 500mg per day. Placebo is given 6 times per day for the second 14 days.	Dietary supplement: Tryptophan; Tryptophan and placebo are given in a crossover design, based on randomisation.
EXPERIMENTAL: Tryptophan second; Placebo is given 6 times per day for the first 14 days. Tryptophan is given for the second 14 days, 6 times 500mg per day.	Dietary supplement: Tryptophan; Tryptophan and placebo are given in a crossover design, based on randomisation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
quarrelsome behaviour	quarrelsome behaviour is measured daily for 28 days using Ecological Momentary Assessment.	28 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
interpersonal behaviour	measures are assessed on a daily basis for 28 days with ecological momentary assessment	28 days
affect	measures are assessed on a daily basis for 28 days with ecological momentary assessment	28 days
perceptions of others	measures are assessed on a daily basis for 28 days with ecological momentary assessment	28 days
social cognitions	measures are assessed daily for 28 days with ecological momentary assessment	28 days

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serotonin transporter polymorphism	Prior to starting the 28 days of social interacton recording participants are instructed about the study procedures. The saliva samples are analyzed for Serotonin transporter polymorphism.	1 day

Collaborators and Investigators

• Sponsor: University of Groningen
• Investigators: Principal Investigator: Marije aan het Rot, Dr., University of Groningen

Study record dates

Study Major Dates

• Study Start: August 1, 2012
• Primary Completion (ACTUAL): January 1, 2014
• Study Completion (ACTUAL): January 1, 2014

Study Registration Dates

• First Submitted: January 24, 2014
• First Submitted That Met QC Criteria: January 29, 2014
• First Posted (ESTIMATE): January 31, 2014

Study Record Updates

• Last Update Posted (ESTIMATE): January 31, 2014
• Last Update Submitted That Met QC Criteria: January 29, 2014
• Last Verified: January 1, 2014

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Psychotropic Drugs; Antidepressive Agents; Antidepressive Agents, Second-Generation; Tryptophan
• Other Study ID Numbers: NL451-09-013 / 2