This essay analyzes the psychiatric treatment of depressed patients, using the case of Alison to illustrate the clinical reasoning cycle. It covers the patient's social situation, mental state examination findings, and the application of DSM-5 diagnostic criteria. The essay emphasizes the importance of collecting and processing information to understand the patient's condition, including social isolation and emotional disturbance. It outlines goals such as reducing anxiety and improving social function, suggesting counseling and social support as key interventions. The nurse's role in assessing outcomes and reflecting on the process is also highlighted, along with the importance of involving the patient's support system. The essay concludes with a reflection on the learning outcomes and the application of MSE techniques and communication skills in developing a treatment plan.