Here is the design of a clinical trial:

Official Title: IPT for Major Depression Following Perinatal Loss: Healing After Loss (HeAL)

Included conditions:
- Major Depressive Disorder

Study Armgroups:
- {'label': 'Interpersonal psychotherapy for major depression following perinatal loss', 'type': 'EXPERIMENTAL', 'description': "Participants in the IPT condition will receive 12 group sessions and 2 individual (pre-group and 1-month booster) sessions as outlined in the manual The individual sessions prepare patients to use the group effectively, to keep group members focused on their treatment goals, and to maintain treatment gains. In addition, 3 of the 12 group sessions will invite women to include their partners or other support people to bolster the woman's social support system and to reduce conflicts over how to react to the loss. These sessions are important because relationship distress is common following perinatal loss. Our IPT intervention allows new women to enter the group every 4 weeks of the 12-week group. Group sessions are semi-structured, and each woman will cover the four group topics three times, approaching each topic from a different stage in the mourning process.", 'interventionNames': ['Behavioral: Interpersonal psychotherapy for major depression following perinatal loss']}
- {'label': 'Coping with Depression', 'type': 'ACTIVE_COMPARATOR', 'description': 'The Coping with Depression (CWD) course is a structured, manualized psycho-educational group treatment for MDD. The CWD course is based on social learning theory which posits that depression is associated with a decrease in pleasant and an increase in unpleasant person-environment interactions. The problems shown by depressed individuals are viewed as behavioral, with cognitive patterns that can be unlearned or relearned. Its effectiveness is comparable to other forms of psychotherapy in depression. The course content is cognitive-behavioral in nature and is designed to train skills that can be used in the alleviation of depression. The skill modules focus on relaxation, cognitive skills, and behavioral activation. As in the pilot trial, CWD will consist of an individual pregroup session, 12 group therapy sessions (allowing new women to enter every 4th session) and a 1-month individual booster session to provide an identical treatment dose as the experimental condition.', 'interventionNames': ['Behavioral: Coping with Depression']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Interpersonal psychotherapy for major depression following perinatal loss', 'description': "Participants in the IPT condition will receive 12 group sessions and 2 individual (pre-group and 1-month booster) sessions as outlined in the manual The individual sessions prepare patients to use the group effectively, to keep group members focused on their treatment goals, and to maintain treatment gains. In addition, 3 of the 12 group sessions will invite women to include their partners or other support people to bolster the woman's social support system and to reduce conflicts over how to react to the loss. These sessions are important because relationship distress is common following perinatal loss. Our IPT intervention allows new women to enter the group every 4 weeks of the 12-week group. Group sessions are semi-structured, and each woman will cover the four group topics three times, approaching each topic from a different stage in the mourning process.", 'armGroupLabels': ['Interpersonal psychotherapy for major depression following perinatal loss'], 'otherNames': ['IPT']}
- {'type': 'BEHAVIORAL', 'name': 'Coping with Depression', 'description': 'The Coping with Depression (CWD) course is a structured, manualized psycho-educational group treatment for MDD. The CWD course is based on social learning theory which posits that depression is associated with a decrease in pleasant and an increase in unpleasant person-environment interactions. The problems shown by depressed individuals are viewed as behavioral, with cognitive patterns that can be unlearned or relearned. Its effectiveness is comparable to other forms of psychotherapy in depression. The course content is cognitive-behavioral in nature and is designed to train skills that can be used in the alleviation of depression. The skill modules focus on relaxation, cognitive skills, and behavioral activation. As in the pilot trial, CWD will consist of an individual pregroup session, 12 group therapy sessions (allowing new women to enter every 4th session) and a 1-month individual booster session to provide an identical treatment dose as the experimental condition.', 'armGroupLabels': ['Coping with Depression'], 'otherNames': ['CWD']}

Primary Outcomes:
- {'measure': 'Time to Major Depressive Disorder recovery', 'description': 'Assessed via the Longitudinal Interview Follow-up Evaluation (LIFE; lower is better)', 'timeFrame': 'censored at 28 weeks, the proposed study duration'}

Please estimate the sample size based on the assumption: 
The assumptions include a 1:1 allocation, power of 0.80, two-sided tests at p=0.05, and a missing/dropout rate of up to 25%.
Sample size
        
          Recovery outcomes
          For the primary outcome of time to MDD recovery (censored at 28 weeks), assuming 1:1 allocation, power 0.80, two-sided tests at p=0.05, and observed estimated HR=1.79, the required number of events is 94 (number of MDEs resolved). By week 28, there were 17 events in the preliminary data (17âwomen had MDD resolved, 11 in the IPT condition and 6 in the CWD condition) out of 45 participants, so the rate of events was 0.38. Thus to have 94 events, total N=246 is required. Given that 90% of pilot trial participants completed at least one follow-up assessment,31 we increased the sample size to 274. Given the observed HR of 5.85 for PTSD in the pilot trial, power for PTSD recovery should be greater than 80%. Tests of mediation in aim 3 will have greater power than the primary outcome because of reduction in error variance when controlling for the mediator.
        
        
          Continuous (secondary) outcomes
          Assuming an unadjusted d=0.32âand a correlation of 0.6 between follow-up measures and 0.3 with baseline (as observed in the preliminary data), the adjusted effect size would be 0.40, and only n=200 participants would be needed before attrition. If study attrition is higher, the study still has >80% power for secondary outcomes (table 3).
          
            Table 3
            
              Power for n=274 for secondary outcomes
            
            
              
                
                  
                  d=0.29
                  d=0.32
                  d=0.35
                
              
              
                
                  10% attrition
                  0.81
                  
0.88

                  0.93
                
                
                  15% attrition
                  0.74
                  0.83
                  0.88
                
                
                  20% attrition
                  0.72
                  0.80
                  0.86
                
                
                  25% attrition
                  0.69
                  0.78
                  0.84