Here is the design of a clinical trial:

Official Title: "Resilient Caregivers" - A Randomized Controlled Trial of a Resilience-based Intervention for Distressed Partner Caregivers of Cancer Patients

Included conditions:
- Distress, Emotional

Study Armgroups:
- {'label': '"Resilient Caregivers"', 'type': 'EXPERIMENTAL', 'description': 'Intervention program', 'interventionNames': ['Behavioral: "Resilient Caregivers"']}
- {'label': 'Control group', 'type': 'OTHER', 'description': 'Care as usual', 'interventionNames': ['Other: Care as usual']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': '"Resilient Caregivers"', 'description': '"Resilient Caregivers" is a 7-session group program developed for partner caregivers of patients with cancer (6 weekly sessions and 1 booster session). Each session takes place in groups of approximately 8 participants and lasts for two-and-a-half hours. Sessions 1 to 3 focuses on the caregiver and introduces the resilience components of coping strategies, meta-reflective skill and clarification of values. Sessions 4 and 5 focuses on these components in the relationship between the caregiver and the cancer patient and social support networks respectively, while Session 6 focuses on resilience in relation to self-care and care for the partner. A booster session will be scheduled one month after the end of Session 6 in order to follow-up on the intervention and allow participants to reflect on the benefits and challenges of the program.', 'armGroupLabels': ['"Resilient Caregivers"']}
- {'type': 'OTHER', 'name': 'Care as usual', 'description': 'The control arm will receive usual care, which implies no systematic support.', 'armGroupLabels': ['Control group']}

Primary Outcomes:
- {'measure': 'Change in symptoms of anxiety', 'description': 'Measured by Generalized Anxiety Disorder-7 (GAD-7); range 0-21; higher scores = more symptoms', 'timeFrame': 'Baseline, 3 months, 6 months and 12 months follow-up'}

Please estimate the sample size based on the assumption: 
Linear mixed model with a random subject effect, four measurements, two groups, 80% power (95% certainty between 75% and 85%), significance level of 0.05.
Sample size and power calculations
        We calculated power simulated from a linear mixed model with a random subject effect, in a set up with four measurements (baseline and three follow-up measurements), and two groups (intervention, control) with no difference at baseline on the primary outcome of anxiety (online supplemental material 1). We plan to include 80 participants to obtain at least 80% power (95% certainty between 75% and 85%) for detecting a minimum difference of â3 points between intervention and control groups at 6-month and 12-month follow-up as measured by the Generalised Anxiety Disorder scale (online supplemental material 1).37 The calculations were carried out using R package simr with an assumed significance level of 0.05.38