American Society of Hematology disorders of the hematopoietic, hemostatic, and lymphatic systems, and disorders of the interaction between blood and the blood vessel wall. An American hematologist has trained in a subspecialty program approved by the American Board of Internal Medicine or the American Board of Pediatrics, or has acquired a comparable education in the field by alternate means, and is Board Certified (or eligible) in the subspecialty of hematology. Diagnostic expertise of a hematologist A hematologist is expert in the investigation, diagnosis, and management of disorders of the aforementioned organ systems through the use of the medical history, physical findings, specialized clinical laboratory
Classification of mental disorders in the 10th century by Arabian psychologist Najab ud-din Unhammad. His nosology included nine major categories of mental disorders, with 30 different mental illnesses in total. Some of the categories he described resembled obsessive-compulsive disorders, delusional disorders, degenerative diseases, involutional melancholia, and states of abnormal excitement. Avicenna (980−1037 CE) in the Canon of Medicine listed a number of mental disorders, including "passive male homosexuality". Laws generally distinguished between "idiots" and "lunatics". Thomas Sydenham (1624–1689), the "English Hippocrates", emphasized careful clinical observation and diagnosis and developed the concept of a syndrome, a group of associated symptoms having a common course, which