Biscuit (bread) cooking, most often based on ground wheat and warmed with gravy. The biscuit emerged as a distinct food type in the early 19th century, before the American Civil War. Cooks created a cheaply produced addition for their meals that required no yeast, which was expensive and difficult to store. With no leavening agents except the bitter-tasting pearlash available, beaten biscuits were laboriously beaten and folded to incorporate air into the dough which expanded when heated in the oven causing the biscuit to rise. In eating, the advantage of the biscuit over a slice of bread was that it was harder,
Substance abuse was the first to recognize substance abuse (including drug abuse) and substance dependence as conditions separate from substance abuse alone, bringing in social and cultural factors. The definition of dependence emphasised tolerance to drugs, and withdrawal from them as key components to diagnosis, whereas abuse was defined as "problematic use with social or occupational impairment" but without withdrawal or tolerance. In 1987, the DSM-IIIR category "psychoactive substance abuse," which includes former concepts of drug abuse is defined as "a maladaptive pattern of use indicated by...continued use despite knowledge of having a persistent or recurrent social, occupational, psychological or physical problem