Working in psychiatric settings can be very stressful, and clinical supervision is a widespread stress-reducing intervention for nursing staff members. Purpose: The aim of this study was to examine factors affecting psychiatric nurses’ participation in supervision and their experienced outcome of clinical supervision. In the paper, we discuss the benefits of working with mixed methods designs. Methods: The study was a sequential mixed methods study. A questionnaire survey included a sample of 136 nurses working in psychiatric hospitals and in community mental health centres. An interview study included 22 of the nurses employed at the psychiatric hospital. Results: The study indicated that clinical supervision was most beneficial for nurses who already had the necessary time, trust, and energy to participate in supervision sessions. Conclusion: Clinical supervision must therefore be organised in ways that facilitate nurses’ opportunities for regular participation in supervision sessions, whereby trusting relationships between participants will grow.