Expired Study
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Philadelphia, Pennsylvania 19104


This study will assess the effectiveness of venlafaxine XR in preventing the relapse of generalized anxiety disorder after 6 months of treatment versus 12 months of treatment.

Study summary:

Generalized anxiety disorder (GAD) is a highly prevalent, chronic psychiatric disorder. Despite the fact that GAD frequently demands prolonged treatment with medication, very little is known about the benefits of long-term treatment. GAD is characterized by 6 months or more of exaggerated worry and tension that is unfounded or much more severe than the normal anxiety most people experience. People with GAD are unable to relax and often suffer from insomnia. Venlafaxine XR, a drug used to treat depression, has been shown to be effective in the short-term treatment of GAD. However, its benefits over a course of more than 8 weeks have not been assessed. This study will evaluate the effectiveness of venlafaxine XR in treating GAD on a long-term basis and preventing the relapse of GAD after 6 months of treatment versus 12 months of treatment. Participants in this double-blind study will first receive 6 months of open-label treatment with venlafaxine XR. Upon completion of this initial phase, participants will be randomly assigned to either continue on venlafaxine XR or begin taking placebo. After 12 months, participants taking venlafaxine XR will be randomly assigned to continue on the drug or switch to placebo. Participants will have 22 study visits over at least 18 months. Follow-up visits will occur 24 months after enrollment. Relapse of GAD will be assessed with the Hamilton Anxiety Scale and Global Severity and Improvement Scale. A variety of methods, including questionnaires and standardized scales, will be used to assess secondary outcomes.


Inclusion Criteria: - GAD diagnosis by structured interview - Hamilton Anxiety Scale score of 18 or MORE - Clinical Global Impressions Severity Scale score of at least 4 - Hamilton Depression Scale score of 18 or less - Hamilton Depression Scale suicide item score less than 2 - Use of an effective form of contraception throughout the study Exclusion Criteria: - Hypersensitivity to venlafaxine XR - History of seizures - Episode of major depressive disorder in the previous 6 months - History of any psychotic illness, bipolar disorder, or dementia - Substance abuse and dependence during the past 6 months - Other anxiety disorders with the exception of social phobia as long as GAD is primary - Regular use of anxiolytics or antidepressants within 7 days of study onset - Use of fluoxetine or monoamine oxidase inhibitors within 28 days of study onset (low dose usage of benzodiazepines will not prevent participation) - Use of other psychotropic medication besides benzodiazepines during the study

Study is Available At:

Original ID:

R01 MH65963



Secondary ID:


Study Acronym:

Brief Title:

Effectiveness of Long-Term Versus Short-Term Treatment of Generalized Anxiety Disorder With Venlafaxine XR

Official Title:

Short-term Versus Long-term Treatment in Generalized Anxiety Disorder

Overall Status:


Study Phase:

Phase 4



Minimum Age:

18 Years

Maximum Age:


Quick Facts

Healthy Volunteers
Oversight Has DMC
Study Is FDA Regulated
Study Is Section 801
Has Expanded Access

Study Source:

National Institute of Mental Health (NIMH)

Oversight Authority:

United States: Federal Government

Reasons Why Stopped:

Study Type:


Study Design:

Allocation: Randomized, Endpoint Classification:

Number of Arms:


Number of Groups:


Total Enrollment:


Enrollment Type:


Overall Contact Information

Official Name:Karl Rickels, MD
Principal Investigator
University of Pennsylvania

Study Dates

Start Date:January 2004
Completion Date:September 2009
Completion Type:Actual
Primary Completion Date:September 2009
Primary Completion Type:Actual
Verification Date:September 2008
Last Changed Date:October 12, 2010
First Received Date:September 12, 2005

Study Outcomes

Outcome Type:Secondary Outcome
Measure:Anxiety, depression, and GAD symptoms
Time Frame:Measured at Months 6, 12, 18, and 24
Safety Issues:False
Outcome Type:Primary Outcome
Measure:Relapse of GAD
Time Frame:Meausured at Months 6, 12, and 24
Safety Issues:False

Study Interventions

Intervention Type:Drug
Name:Venlafaxine XR
Description:All participants will take venlafaxine for 6 months. After this initial 6 months, participants who are not randomized to placebo will continue to take venlafaxine.
Arm Name:1
Intervention Type:Drug
Description:After initial treatment with venlafaxine, some participants will be randomized to take placebo for 6 months in the second phase of the study and then to switch back to venlafaxine or continue with placebo for an additional 6 months.
Arm Name:2

Study Arms

Study Arm Type:Experimental
Arm Name:1
Study Arm Type:Experimental
Arm Name:2
Description:Venlafaxine and placebo

Study Agencies

Agency Class:NIH
Agency Type:Lead Sponsor
Agency Name:National Institute of Mental Health (NIMH)

Sample and Retention Information

There are no available Sample and Retention Information

Study References

There are no available Study References

Data Source: ClinicalTrials.gov

Date Processed: January 21, 2020

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