Sub-chronic Effects of 5-hydroxytryptophan on Mood and Emotional Processing in Healthy Volunteers

NCT ID: NCT01514409

Last Updated: 2012-01-23

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 33 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2011-05-31
• Study Completion Date: 2011-08-31

Brief Summary

5-hydroxytryptophan (5-HTP) is a nutritional supplement sold in many health food stores, and is taken in order to raise levels of serotonin in the brain. Serotonin is a neurotransmitter that is involved in the regulation of mood.

Previous research has assessed the effects of raising serotonin levels using tryptophan (the precursor of 5-HTP) and serotonergic antidepressants on emotional processing in healthy volunteers. However, to date there has been no human trial investigating the effects of 5-HTP on emotional processing in healthy volunteers.

Thus, the current study aims to assess the effects of 5-HTP, on emotional processing and mood in healthy volunteers.

Detailed Description

The serotonin precursor 5-HTP is sold as a nutritional supplement and has been used to offset low mood for over 30 years due to its ability to raise levels of neural serotonin. However, evidence for the efficiency of 5-HTP is limited and the mechanism of action of 5-HTP in offsetting low mood has not been well-characterised.

The current study assessed the ability of 5-HTP to induce biases for positive emotional material in healthy volunteers, similar to those induced by serotonergic antidepressants and the nutritional supplement tryptophan. The effects of 5-HTP on subjective mood and depressive symptoms were also assessed.

Participants were randomised to receive either 150mg of 5-HTP or placebo daily for 14 days. Depressive symptoms and subjective mood were assessed pre- and post-intervention. Emotional processing was assessed on the 15th day using a battery of emotionally valenced cognitive tasks.

Conditions

Mood

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

5-Hydroxytryptophan

Group Type: EXPERIMENTAL

5-Hydroxytryptophan

Intervention Type: DIETARY_SUPPLEMENT

Thirty-three participants were randomly allocated in a double-blind manner to receive either 3x50mg capsules of 5-HTP or placebo (silica) for 14 days.

5-HTP is produced commercially by extraction from the seeds of the African plant griffonia simplicifolia.

Placebo

Group Type: PLACEBO_COMPARATOR

Pharmaceutical grade silica

Intervention Type: DIETARY_SUPPLEMENT

Pharmaceutical grade silica was utilized as placebo

Interventions

5-Hydroxytryptophan

Thirty-three participants were randomly allocated in a double-blind manner to receive either 3x50mg capsules of 5-HTP or placebo (silica) for 14 days.

5-HTP is produced commercially by extraction from the seeds of the African plant griffonia simplicifolia.

Intervention Type: DIETARY_SUPPLEMENT

Pharmaceutical grade silica

Pharmaceutical grade silica was utilized as placebo

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

Inclusion Criteria

• Male/Female
• Healthy
• Aged 18-65
• Not taking any herbal or prescription medications (excluding contraceptive pill)
• Free from depressive illness or mood disorder for the last 6 months
• Free of physical illness

Exclusion Criteria

• Physically ill
• History of medical illness
• Current or previous (6 month) history of psychiatric disorder
• Pregnant/breastfeeding
• Allergy or hypersensitivity to any of the ingredients contained in the investigational product
• Taking any medication (excluding contraceptive pill)

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Northumbria University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

Northumbria University

Newcastle upon Tyne, , United Kingdom

Countries

United Kingdom

Other Identifiers

24AQ1

Identifier Type: -

Identifier Source: org_study_id