Abnormal psychology, also called psychopathology, is the scientific study of psychological or mental disorders. These disorders affect the way people think, speak, feel, and behave. The term abnormal can refer to something that is strange or rare. However, standards of behavior differ among societies and change as social conditions and customs change. The term abnormal generally refers to a pattern of thoughts, feelings, and behavior that is thought to be a result of a biological or psychological cause and that leads to significant distress, disability, or danger to oneself or others. Psychologists do not consider behavior that is simply different to be a mental disorder.