Now in an extensively revised third edition with 65% new material, this is the authoritative reference on posttraumatic stress disorder (PTSD). Contributors examine the breadth of current knowledge on the mechanisms by which stressful events can alter psychological processes, brain function, and individual behavior. Risk and protective factors across development and in specific populations are explored. Reviewing the state of the science of assessment and treatment, the volume covers early intervention and evidence-based individual, couple/family, and group therapies. Conceptual and diagnostic issues are addressed and key questions for the next generation of researchers are identified.