Here is the design of a clinical trial:

Official Title: Transcranial Direct Current Stimulation (tDCS) Cost-utility-analysis in Medical Care on Depressive Episode With One Drug Therapy Failure.

Included conditions:
- Depression

Study Armgroups:
- {'label': 'Usual care and tDCS (Arm A)', 'type': 'EXPERIMENTAL', 'description': 'Arm A patient receives a first tDCS treatment in association with usual care (medication, psychotherapy...). If the patient is responding to tDCS, he can have other tDCS treatments in case of relapse.', 'interventionNames': ['Other: tDCS associated with usual care']}
- {'label': 'Usual care without tDCS (Arm B)', 'type': 'ACTIVE_COMPARATOR', 'description': 'Arm B patient receives usual care: medication management and psychotherapy.', 'interventionNames': ['Other: Usual care']}

Interventions:
- {'type': 'OTHER', 'name': 'tDCS associated with usual care', 'description': 'A tDCS cure will be given to the group "tDCS", one week after their randomization.\n\nThis will be done in association with usual care: medication and psychotherapy Parameters: Anodal stimulation on dorso-lateral prefrontal cortex left, 2mA current.\n\nTreatment will consist of 15 days with 30 minutes stimulation per day, 5 days a week for 3 weeks.', 'armGroupLabels': ['Usual care and tDCS (Arm A)']}
- {'type': 'OTHER', 'name': 'Usual care', 'description': 'Medication and psychotherapy as prescribed in usual care', 'armGroupLabels': ['Usual care without tDCS (Arm B)']}

Primary Outcomes:
- {'measure': 'Cost-utility ratio, according to collective perspective of tDCS use in depression compared to usual care without active tDCS.', 'description': 'The utility will be measured by :\n\nQuality Adjusted Life Year (QALYs) as estimated from responses to the Euroqol-5 Dimensions (EQ-5D) health-related quality of life questionnaire. The questionnaire focuses on 5 dimensions: mobility, personal autonomy, current activities, pain/discomfort and anxiety/depression. For each of these dimensions, 5 answers are possible.\n\nThe costs will be measured by the addition of the following costs:\n\nDrugs dispensing via Health insurance database "National system of information of the French health insurance" (SNIIRAM), hospitalizations, work stoppages and care consumption collected in a declarative patient questionnaire.', 'timeFrame': '12 months'}

Please estimate the sample size based on the assumption: 
5% (two-tailed) type I error, 80% power, 10% attrition rate
Sample size calculation
          To our knowledge, no published study has evaluated the quality of life, healthcare resource consumption and costs associated with tDCS treatment for depression, meaning there is no precedent for establishing the number of subjects needed for our study with the formula by Glick.46 We therefore determined this number using a clinical efficacy criterion.
          We hypothesised tDCS-TAU response rate of 60% at M
12
14 47 and a TAU-only response rate of 40%.5 Assuming a 5% (two-tailed) type I error, a power of 80% and an attrition rate of 10%, a total of 214 subjects are required (107 subjects per arm) according to SAS software V.9.4.