• Cardiorespiratory fitness [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  

• Weight [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  
• Waist circumference [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  
• Physical activity [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  
• Health status [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  
• Center for Epidemiology Depression Scale [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  
• Exercise-related self-efficacy [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  
• General perceived efficacy [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  
• Participation [ Time Frame: Measured at Month 4 ] [ Designated as safety issue: No ]
  

People with serious mental illnesses (SMIs) are, by definition, significantly functionally impaired by the illness for an indefinite period of time. Schizophrenia, major depression, and bipolar disorder are considered SMIs. Severe anxiety disorders, cognitive disorders, and some personality disorders are sometimes categorized as SMIs, as well. The rate of obesity among people with SMIs is higher than that of people without mental illnesses. This disparity may be due to the negative symptoms that people with SMIs experience, such as vulnerability to stress, extreme dependency, and lack of motivation. This study will design and test a culturally appropriate physical activity intervention based on a peer support model for people with SMIs in an urban community psychiatry program. The intervention will be evaluated to determine its effectiveness in increasing physical activity and effecting health behavior change in people with SMIs.

Participants in this 4-month, open-label study will be randomly assigned to participate in either a physical activity intervention with peer support (PA+PS) or a physical activity intervention without peer support (PA). Participants in the PA+PS group will have three exercise sessions each week, which will include group exercise classes and open gym hours for supervised individual exercise. They will also meet with a peer educator once a week for 15 minutes. Peer educators will provide emotional, informational, instrumental, and appraisal support that is aimed to motivate participants to partake in the exercise sessions. Participants in the PA group will attend the three weekly exercise sessions but will not attend meetings with the peer educator. All outcomes will be assessed at a follow-up visit at the end of the intervention.