The purpose of this study is to determine the efficacy of exercise training relative to pharmacologic treatment in clinically depressed older adults aged 50 years and older. This study is a randomized controlled trial of exercise training and/or pharmacologic treatment (sertraline or Zoloft) in which subjects undergo comprehensive assessments including a clinical diagnostic evaluation, exercise treadmill testing, and medical examinations. Following this assessment, subjects are classified as mild/moderately or severely depressed and within these groups randomly assigned to one of three treatment groups: (a) medication (Zoloft); (b) aerobic exercise training; or (c) medication and exercise. Following the completion of the 4-month treatment program, subjects undergo a third evaluation at 6-month follow-up, and a fourth evaluation at 1 year follow-up. This study hypothesizes that: (1) an aerobic exercise program is feasible among older depressed patients, and the extent of improvement in cardiorespiratory function will be comparable to that of normal subjects; (2) an aerobic exercise program will be associated with comparable reductions in depression in mild-moderately depressed patients relative to mild-moderately depressed patients receiving medication alone; (3) drug therapy will be superior to exercise alone in the treatment of severely depressed patients; (4) aerobic exercises combined with medication will be superior to medication alone among severely depressed patients; (5) aerobic exercise training in mild-moderately depressed patients will be associated with less relapse at 6 months than patients receiving drug therapy alone; and (6) at 6 month and 1 year follow-ups, there will be greater relapse in the severely depressed patients receiving drug alone compared to patients who receive both drug and exercise training. This past year, we recruited 1 additional participant, a white male who was classified as severely depressed. This participant dropped out of the study following his Time 1 assessment. One hundred and fifty-six subjects have been enrolled during the past four years. Of these 156 subjects, 43 are male and 113 are female; 66 are classified as severe and 90 are classified as mild/moderate depressives. The ethnic breakdown of these 156 subjects is as follows: 133 Caucasions ( 39 male, 94 female); 18 African-Americans (3 male, 15 female); 3 Hispanic subjects ( 1 male, 2 female); 1 Native American female; and 1 Iranian female. Our protocol states that our ethnic breakdown will be 75% white and 25% minority, which we attempted to reach by participation in health fairs, contacting churches, and presentations. However, our total ethnic minority recruitment was 14.7%. In addition, our gender breakdown is currently 72% female and 28% male, which meets our protocol criteria (50% female and 50% male). In total, thirty-two (21%) subjects dropped out prematurely from the study (7 from medication only, 14 from exercise only, and 11 from exercise/medication). All active subjects (134 participants) have completed the four-month treatment and 6-month follow-up portions of the study. To date, 80 active subjects have completed the 18-month follow-up portions of the study. There are no plans to recruit further patients. Future plans include completing the 18-month follow-up assessments for all active participants, which is expected to continue through September, 1999. Additionally, we will be working on data analyses and manuscript publications and presentations. The information obtained from this study will have significant practical implications for the treatment of depression by clarifying the psychological benefits of exercise for older adults.