Common mental illnesses have been diagnosed separately in recent years, but what is seldom understood is that they are all linked together, often much more closely than other disorders. In particular, combined anxiety and depression linked to personality disturbance, generally known as neuroticism, is very common. In the absence of awareness of its importance, this frequently leads to wrong clinical decisions and poor outcomes for patients. This book focuses on the concept of neurosis, tracing its history as a concept, its abolition from the DSM, the purpose and importance of the Nottingham Study of Neurotic Disorder, the re-definition of neurosis as the general neurotic syndrome, and its recently updated evidence base. Written for psychiatrists, psychologists and researchers, this book shows how recognising these combined common disorders is absolutely necessary for mental health practice, and urges that it is time that we re-examine our treatment priorities.