No one definition of abnormality seems adequate, although some features are usually fundamental to what we mean by abnormality. Mental disorders are generally regarded as bad, and therefore values are inherent in our judgments. However, our society has no systematic value system, usually meaning that the judgments about what values to apply are often controversial. Review of Major Concepts Abnormal behaviors have been widely observed throughout history. Mental illness is often an important factor in major life events of affected persons.
Many mental illnesses are widespread.
Perhaps about half of all persons will experience such a disorder in one's life. Most people will be affected by the disorder of someone close to them. Although these disorders are often important, remember that affected individuals often function well and are not simply defined by their disorder. Defining abnormality is complex, with no one definition being adequate.