This text provides a comprehensive and evidence-based introduction to psychiatric mental health assessment and diagnosis in advanced nursing practice. Taking a clinical, case-based approach, this textbook is designed to support graduate nursing students who are studying psychiatric mental health nursing as they develop their reasoning and decision-making skills. It presents: Therapeutic communication and psychiatric interviewing techniques, alongside basic psychiatric terminologies. The major psychiatric diagnoses, drawing on the DSM-5. A step-by-step guide to conducting a comprehensive psychiatric mental health assessment. Case examples demonstrating assessment across major psychopathologies. Good practice for conducting mental health evaluations. This is an essential text for all those undertaking psychiatric mental health nurse practitioner programs and a valuable reference for advanced practice nurses in clinical practice.