Exercise Training for the Treatment of Generalized Anxiety Disorder

• Generalized Anxiety Disorder (GAD) Remission as Measured by Anxiety Disorders Interview Schedule-Adult Version (ADIS-IV) Severity Ratings [ Time Frame: Pre- and post- 6 week training intervention ] [ Designated as safety issue: No ]
  GAD is characterized by persistent excessive or pathologic worry most days for at least 6 months about activities of daily life that is difficult to control and associated with at least 3 of the following symptoms: restlessness, feeling on edge, being easily fatigued, difficulty concentrating, irritability, muscle tension, and sleep difficulty. Symptoms are not caused by a substance or disorder, but cause significant distress or functional impairment. Remission was measured using the ADIS-IV from 1-16 days following the 6-week intervention.
• Worry Symptoms [ Time Frame: Baseline, Week 2, Week 4, Week 6 ] [ Designated as safety issue: No ]
  Worry symptoms, hallmark symptoms of GAD, were assessed using the Penn State Worry Questionnaire (PSWQ). The PSWQ is a 16-item self-report questionnaire that measures pathological worry symptoms. Participants rate items from 1 "not at all typical of me" to 5 "very typical of me." Scores range from 16 to 80, with higher scores indicated exacerbated worry symptoms. Symptoms were assessed at baseline and at the beginning of the second weekly session during weeks 2, 4, and 6.

The purpose of this study is to compare the effects of 6 weeks of endurance or strength training and a wait list comparison condition on symptoms of Generalized Anxiety Disorder (GAD).

• Other: Strength Training
  6 weeks of strength training exercise sessions involving leg press, leg curl, and leg extension exercises twice weekly at an intensity progressing from 50% to 75% of predicted one-repetition maximum across the 6 weeks of the trial.
• Other: Endurance Training
  Six weeks of lower-body dynamic cycling exercise completed on an electronically-braked cycle ergometer twice weekly. The intervention will be matched to the strength training intervention on total work completed, total time actively engaged in exercise, a focus on leg muscles, and load (intensity) progression across the 6 week training protocol.

• Experimental: Strength Training
  Lower-body strength training exercise twice weekly for 6 weeks at an intensity progressing from 50% to 75% predicted one-repetition maximum
  Intervention: Other: Strength Training
• Experimental: Endurance Training
  Six-week lower-body dynamic cycling exercise condition completed twice weekly and matched to the strength training arm on total work completed, total time actively engaged in exercise and load progression.
  Intervention: Other: Endurance Training
• No Intervention: Waiting List Control
  Waiting list control condition in which participants will maintain their current lifestyle and will not enter a six-week exercise training intervention, but will complete outcome measures along the same time progression as the intervention arms.

Inclusion Criteria:

• Women aged 18-39 years
• Principal diagnosis of Generalized Anxiety Disorder according to DSM-IV diagnostic criteria (comorbidities will be acceptable as long as Generalized Anxiety Disorder is the principal diagnosis)

Exclusion Criteria:

• A score of less than 45 on the Penn State Worry Questionnaire
• A score of less than 7 on the Generalized Anxiety Disorder section of the Psychiatric Diagnostic Screening Questionnaire
• Expending greater than 250 kilocalories per kilogram body weight per week as measured by a 7-day physical activity recall questionnaire
• Engaging in greater than 6 exercise bouts in the month prior to recruitment
• Pregnancy
• Any medical contraindications (cardiovascular or musculoskeletal) to exercise training according to American College of Sports Medicine guidelines