Clinical psychology involves the scientific study and application of psychology to understand, prevent, and relieve psychologically-based distress. The field aims to promote well-being and personal development through practices like psychological assessment, psychotherapy, research, teaching, and consultation. Clinical psychology has evolved from pseudoscientific 18th century practices to a modern scientific discipline, influenced by thinkers like Sigmund Freud and developments like standardized testing during World Wars I and II. It encompasses diverse theoretical perspectives including behavioral, cognitive, psychodynamic, humanistic, family systems, and emerging models like positive psychology.