Neuroimaging of St. John's Wort-Induced Changes of Serotonin Metabolism in Normal Subjects

March 3, 2008 updated by: National Institute of Mental Health (NIMH)

Serotonin Transporter Availability and Mood State in Normal Volunteers Taking Hypericum Perforatum (St. John's Wort)

St. John's Wort is a popular dietary supplement that many people take to elevate mood or relieve stress. This study will test in normal volunteers whether this preparation may alter mood and if so, by what means. Animal studies suggest that St. John's Wort may work similarly to some antidepressants that affect levels of the chemical serotonin in the brain.

Participants in this study must also be enrolled in NIMH protocol #98-M-0094 (SPECT Imaging of Dopamine and Serotonin Transporters in Neuropsychiatric Patients and Normal Volunteers) and protocol #91-M-014 (MRI Imaging of Neuropsychiatric Patients and Controls). Separate consent forms are required for each study. Candidates will undergo medical and psychiatric evaluations that may include blood and urine tests, electroencephalogram and electrocardiogram.

Normal volunteers will have a mood assessment at the beginning of the study. They will then be randomly assigned to take either placebo (a pill with no active ingredient) or St. John's Wort 3 times a day for 2 weeks, and will be told what they are taking. After an 11-week hiatus, they will again start treatment on the same schedule, but will not be told which preparation they are receiving. Each evening during the 2-week treatment periods, subjects will complete a brief self-rating mood assessment questionnaire. At the end of each treatment period, they will undergo SPECT brain imaging (a type of CT scan) to determine dopamine and serotonin distribution and density in the brain.

For this procedure, study subjects take three drops of potassium iodide solution within 24 hours before the scan and two drops nightly for 3 days following the procedure. About 10 ml (less than two teaspoons) of blood are drawn before a radioactive tracer is injected. SPECT imaging is done the next day. After about 1 hour of imaging, subjects are given either a placebo or St. John's Wort, and then imaging continues for another 2 hours. During the procedure, up to five blood samples of 6 ml each may be drawn. At some point during the study, a MRI scan of the brain will be done.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Extracts of hypericum perforatum (St. John's wort) have become increasingly popular for the treatment of mood disorders. Hypericum extracts have been approved in Germany for the treatment of mild to moderate depression and are now available in standardized preparations. In the United States, hypericum extracts are frequently purchased as over the counter preparations. Inhibition of the serotonin transporter, similar to clinically used selective serotonin reuptake inhibitors (SSRIs), has been suggested as a possible mechanism of action for the antidepressant properties of hypericum extracts. We propose to study the effects of hypericum extracts on mood states in normal volunteers who are concurrently volunteering under NIMH protocol 98-M-0094 for SPECT imaging of serotonin and dopamine transporter availability with [I-123] Beta-CIT. A placebo-controlled, double-blind, within-subject design will be employed with two two-week periods of drug/placebo administration, clinical assessment and SPECT imaging separated by eleven weeks. We plan to test three hypotheses: 1) that hypericum alters mood state, 2) that hypericum reduces serotonin transporter availability, and 3) that these actions are quantitatively associated with one another.

Study Type

Observational

Enrollment

13

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • National Institute of Mental Health (NIMH)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Free of concomitant medications and must be willing to take hypericum for a period of two weeks and a placebo for two weeks.

No subjects with a relevant Axis I or Axis II disorder.

No subjects with concomitant medical or neurological disorders which require ongoing medication, or which may affect the central nervous system; or taking medication with which St. John's wort may interact.

Must not be pregnant.

Must not be breastfeeding.

No subjects with a prior reaction to iodine, iodine compounds, or shellfish.

No subjects with a history of thyroid disease or dysfunction.

No subjects with a history of recent substance abuse.

No subjects with metal objects in their bodies.

No subjects with a prior adverse reaction to hypericum extracts.

No women who taking birth control pills.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institute of Mental Health (NIMH)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 1999

Study Completion

June 1, 2002

Study Registration Dates

First Submitted

November 3, 1999

First Submitted That Met QC Criteria

November 3, 1999

First Posted (Estimate)

November 4, 1999

Study Record Updates

Last Update Posted (Estimate)

March 4, 2008

Last Update Submitted That Met QC Criteria

March 3, 2008

Last Verified

June 1, 2002

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 990151
  • 99-M-0151

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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