• Difference in average pain intensity on Brief Pain Inventory [ Time Frame: Between 2 weeks and 12 weeks ] [ Designated as safety issue: No ]
• Difference in pain intensity on Western Ontario McMasters University Osteoarthritis Index (WOMAC) [ Time Frame: Between 2 weeks and 12 weeks ] [ Designated as safety issue: No ]

• Difference in pain interference on Western Ontario McMasters University Osteoarthritis Index (WOMAC) [ Time Frame: Between 2 and 12 weeks ] [ Designated as safety issue: No ]
• Difference in role function as assessed by the Sheehan Disability Scale [ Time Frame: Between 2 and 12 weeks ] [ Designated as safety issue: No ]
• Difference in observed physical function as assessed by the Aggravated Locomotor Function Score [ Time Frame: Between 2 and 12 weeks ] [ Designated as safety issue: No ]

This will be a single-blind, placebo-run-in trial. Subjects will be informed that they may receive Venlafaxine or placebo during the course of the trial. All subjects will, in fact, receive placebo for the first two weeks. All subjects will then be placed on 150-225 mg per day of venlafaxine. Primary outcome assessment will compare pain intensity at 2 weeks (after placebo) to that at 12 weeks (after 10 weeks of Venlafaxine treatment).

Study Hypothesis:

In subjects who continue to have activity-limiting osteoarthritis pain after treatment with acetaminophen or non-steroidal anti-inflammatory agents, 150-225 mg Venlafaxine per day over 10 weeks will provide significant additional pain relief over that achieved with placebo (more than 30% reduction after Venlafaxine treatment).

• Osteoarthritis
• Pain

Inclusion Criteria:

• Age 50 - 80 years
• Physician diagnosis of OA in hip, knee or spine
• Significant activity limitation due to pain for at least one month on the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) and average pain more than 5/10 on Brief Pain Inventory despite adequate treatment with acetaminophen or NSAIDs (This will identify an OA group with significant psychological distress and a desire for treatment).
• Depression status is not restricted, but will be monitored with PRIME-MD interview and the SCL-20. We anticipate depressive symptoms will be common in this population due to the above requirement for activity limitation.

Exclusion Criteria:

• Cannot read and write English
• Significant cognitive impairment
• History of psychosis or mania
• Current suicidal ideation
• Current substance abuse or dependence
• Current use of opioids or any antidepressant medication
• Use of investigational drug within the past month