Mental disorder is a psychological pattern or anomaly, potentially reflected in behaviour, that is generally associated with distress or disability, and which is not considered part of normal development in a person's culture. The recognition and understanding of mental health conditions have changed over time and across cultures and there are still variations in definition, assessment and classification. The causes of mental disorders are varied and in some cases unclear, and theories may incorporate findings from a range of fields. Services are based in psychiatric hospitals or in the community, and assessments are carried out by psychiatrists, clinical psychologists and clinical social workers, using various methods but often relying on observation and questioning. Mental Disorder explains the latest research on mental disorders. It serves as an essential start to mastering the science and art of clinical practice.