The document discusses psychopathology and the signs and symptoms of mental disorders. It begins by defining key terms like symptoms, signs, and syndromes. It then describes the characteristics of mental disorders and explains descriptive psychopathology. Descriptive psychopathology involves precisely observing behaviors and understanding subjective experiences in order to diagnose and understand mental disorders. The document outlines the principal categories of symptoms seen in mental disorders, including perceptual abnormalities, thought content and form, affect, motor activity, and others. It provides examples of specific symptoms within each category, such as types of hallucinations and delusions.