The Addicted Brain

example is inflammation: perhaps the simplest form of pathology. It has well defined characteristics which, for many of the old continent, were described in latin: rubor, tumor, calor, dolor, and functio lesa. When these characteristics are present, the pathology/disease can be diagnosed. If it occurs in the lung it will indicate pneumonia, in the kidney nephritis etc. Likewise, a brain chronically receiving drugs changes its physiology, its biochemistry, and even its anatomy in its most intimate structure such as dendritic spines and genes. An excellent example (but many other exist) is provided by one of the most intensely studied neuronal systems of the brain in addiction studies: the dopamine system.