Chronic nausea and vomiting: new insights and approach to treatment.

Chronic vomiting of unclear etiology has been given a number of names over time. For many years, it was known as "psychogenic" vomiting because a psychiatric etiology was considered the most likely cause. More recently, the concepts of cyclic vomiting syndrome (CVS) and functional vomiting (FV) have been proposed to better explain this perplexing phenomenon. CVS is a dramatic clinical syndrome characterized by intense episodes of vomiting lasting over a period of days but alternating with periods of intense quiescence. FV, as defined by the Rome II diagnostic criteria, is vomiting of at least 3 months, which need not be consecutive, in the preceding year with at least three separate vomiting episodes in a week. It is found in the absence of obvious metabolic, structural, or psychiatric disorders which could explain the vomiting (Table 1). It will be the purpose of this article to review the history of chronic vomiting from a nomenclature perspective. Methodologic limitations of early studies will be described as well as more contemporary reviews that used updated methodologic approaches to describe this perplexing problem.