ABSTRACT
This chapter begins to visualise scenarios that reader might experience in reader clinical practice, and to think about the questions that follow. It explores and critiques the concept of diagnosis. The chapter also explores psychiatric diagnosis from multiple perspectives, including service user, carer, medical and sociological approaches. It addresses theories of causality of mental illness, classification of mental illness, diagnostic systems and processes, diagnosing mental illness, labelling theory, prejudice and discrimination and implications for nursing. Over a long time period, mental health research has sought evidence to demonstrate that mental illness is a genetically determined disorder—that is, it runs in families. The chapter provides a brief overview of some of the major psychological theories and how they are used to explain the existence of mental illness, including psychoanalytic theory, behavioural psychology, cognitive psychology and humanistic psychology. Classification of mental illness is of particular benefit to the medical model approach to care and treatment.
