White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells.
Nicotine dependence is now recognized as a psychoactive substance dependence disorder (DSM-IV, ICD-10). Under the DSM-IV criteria smokers are classified as dependent if they exhibit impaired control and continue to smoke despite awareness that it exacerbates a medical condition, and if they experience withdrawal symptoms when abstaining from smoking, or if they have a history of unsuccessful attempts at quitting.
Chapter 3: The DSM-IV System 94 3.6.1 Limitations of the DSM-IV The DSM-IV has come under various criticisms over the years, since there is no objective diagnostic test or measurement for mental illness in the field of mental health.hapter 3: The DSM-IV System 75 Another definition by Sands (1991:15) is that mental health is a term used to describe either a level of cognitive or emotional well-being or an absence of a mental disorder.