Here is the design of a clinical trial:

Official Title: Internet-delivered Cognitive Behaviour Therapy for Anxiety Related to Asthma: A Randomized Controlled Trial

Included conditions:
- Asthma
- Anxiety

Study Armgroups:
- {'label': 'Internet-CBT', 'type': 'EXPERIMENTAL', 'description': 'The internet-CBT will comprise 8 weekly modules with therapist-support, encouraging exposure for fear of asthma symptoms while ensuring a stable asthma medication through a written medical plan on medical adherence Participants work independently from home with the treatment and receive weekly support from their psychologist through written messages online.', 'interventionNames': ['Behavioral: Exposure-based Internet-CBT']}
- {'label': 'Treatment as usual', 'type': 'OTHER', 'description': 'Patients randomized to treatment as usual will receive the same medical information that participants in the Internet-CBT get, with physiological information about asthma and the importance of medical adherence to achieve well controlled asthma, but without the exposure-based treatment and no therapist support. All participants in both conditions can use any other available treatment, but psychological, from pre-assessments to 2 months after treatment completion. Participants in this arm will be crossed over to Internet-CBT after the primary endpoint at to 2 months follow up.', 'interventionNames': ['Other: Treatment as usual']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Exposure-based Internet-CBT', 'description': 'Internet-CBT for anxiety-related asthma 8 weekly modules of CBT delivered over the internet and targeting enhanced function and decreased symptoms of anxiety. Participants work independently from home with the treatment and receive support from experienced Internet-CBT Psychologists through written messages in the secure platform. All participants in both conditions can use any other available treatment (TAU), but psychological, from pre-assessments to 2 months after treatment completion.', 'armGroupLabels': ['Internet-CBT'], 'otherNames': ['Online exposure therapy']}
- {'type': 'OTHER', 'name': 'Treatment as usual', 'description': 'Patients randomized to treatment as usual will receive the same medical information that participants in the Internet-CBT get, with physiological information about asthma and the importance of medical adherence to achieve well controlled asthma, but without the exposure-based treatment and no therapist support. All participants in both conditions can use any other available treatment (TAU), but psychological, from pre-assessments to 2 months after treatment completion.', 'armGroupLabels': ['Treatment as usual'], 'otherNames': ['TAU']}

Primary Outcomes:
- {'measure': 'Catastrophizing about asthma Scale', 'description': 'Change in catastrophizing cognitions about asthma measured with a self-rating scale at baseline, weekly during treatment, at 16 weeks, 36 weeks and 12 months for analysis of effect.', 'timeFrame': 'Time Frame: Baseline to 16 weeks; baseline to 36 weeks; baseline to 12 months.'}

Please estimate the sample size based on the assumption: 
80% power at alpha-level 0.05, SD of 1.0
Sample size and power
        A power analysis using G*power demonstrated that the sample size of 90 will provide 80% power at alpha-level 0.05 to detect a moderate between-group effect size (Cohenâs d=0.6) on the primary outcome (catastrophising about asthma) from prerandomisation to 16 weeks postrandomisation. The analysis is based on the treatment effects in the feasibility study. We assumed an SD of 1.0.