Provides clinical descriptions, diagnostic guidelines, and codes for all mental and behavioral disorders commonly encountered in clinical psychiatry. The book was developed from chapter V of the Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10). The clinical descriptions and diagnostic guidelines were finalized after field testing by over 700 clinicians and researchers in 110 institutes in 40 countries, making this book the product of the largest ever research effort designed to improve psychiatric diagnosis. Every effort has been made to define categories whose existence is scientifically justifiable as well as clinically useful. The classification divides disorders into ten groups according to major common themes or descriptive likeness, a new feature, which makes for increased convenience of use. For each disorder, the book provides a full description of the main clinical features and all other important but less specific associated features. Diagnostic guidelines indicate the number, balance, and duration of symptoms usually required before a confident diagnosis can be made. Inclusion and exclusion criteria are also provided, together with conditions to be considered in differential diagnosis. The guidelines are worded so that a degree of flexibility is retained for diagnostic decisions in clinical work, particularly in the situation where provisional diagnosis may have to be made before the clinical picture is entirely clear or information is complete.