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

University of Pennsylvania

Status and phase: Completed; Phase 4

Conditions: Anxiety Disorders

Treatments: Drug: Placebo; Drug: Venlafaxine XR

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT00183274

MH65963

R01MH065963 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

This study will assess the effectiveness of venlafaxine XR, randomized to either venlafaxine XR or placebo in preventing the relapse of generalized anxiety disorder after 6 months of treatment versus 12 months of treatment.

Full description

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.

Enrollment: 268 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

---

268 participants in 6 patient groups, including a placebo group

Open-Label Group

Active Comparator group

Description:

6-month randomized phase of Venlafaxine XR at a flexible dose of 75 - 225 mg/d

Treatment:

Drug: Venlafaxine XR

Double-Blind Drug Group

Active Comparator group

Description:

6-month randomized, double-blind phase of Venlafaxine XR at a flexible dose of 75 - 225 mg/d occurring between months 6 - 12 of the study

Treatment:

Drug: Venlafaxine XR

Double-Blind Placebo Group

Placebo Comparator group

Description:

6-month randomized, double blind phase of placebo occurring between months 6 - 12 of the study

Treatment:

Drug: Placebo

Double-Blind Drug-After-Drug Group

Active Comparator group

Description:

6-month randomized, double blind phase of Venlafaxine XR at a flexible dose of 75 - 225 mg/d occurring between months 13 - 19 of the study

Treatment:

Drug: Venlafaxine XR

Double-Blind Placebo-After-Drug Group

Placebo Comparator group

Description:

6-month randomized, double blind phase of placebo occurring between months 13 - 19 of the study

Treatment:

Drug: Placebo

Double-Blind Placebo-After-Placebo Group

Placebo Comparator group

Description:

6-month randomized, double blind phase of placebo occurring between months 13 - 19 of the study

Treatment:

Drug: Placebo