Social Behaviour
Conditions
Brief summary
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.
Interventions
DIETARY_SUPPLEMENTTryptophan
Tryptophan and placebo are given in a crossover design, based on randomisation.
Sponsors
University of Groningen
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| quarrelsome behaviour | 28 days | quarrelsome behaviour is measured daily for 28 days using Ecological Momentary Assessment. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| interpersonal behaviour | 28 days | measures are assessed on a daily basis for 28 days with ecological momentary assessment |
| affect | 28 days | measures are assessed on a daily basis for 28 days with ecological momentary assessment |
| perceptions of others | 28 days | measures are assessed on a daily basis for 28 days with ecological momentary assessment |
| social cognitions | 28 days | measures are assessed daily for 28 days with ecological momentary assessment |
Other
| Measure | Time frame | Description |
|---|---|---|
| Serotonin transporter polymorphism | 1 day | 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. |
Outcome results
None listed