"Abnormal Psychology" focuses on the origins of abnormal behavior and its evolution into a scientific principle. The theoretical models of mental illness will be discussed along with the components of anxiety disorder, schizophrenia, and eating disorders. Lifespan development can contribute to the interpretation of abnormal behavior. Different concepts will be discussed relating to abnormal psychology including marriage, family, and religion. Abnormal behavior may be in existence since the beginning of mankind yet its study is barely over 100 years.