Involuntary wetting is one of the most common symptoms of childhood, affecting 10% of all 7-year-olds at night and 3% during the day (Hellström, Hanson, Hansson, Hjälmas, & Jodal, 1990). It comprises a heterogeneous group of disorders that differ regarding aetiology, pathophysiology, clinical symptoms, and therapy. Day wetting was last reviewed in the Journal of Child Psychology and Psychiatry in 1979 (Berg, 1979). In the past two decades a wealth of information on the pathophysiology of nocturnal enuresis, as well as of diurnal wetting, has been won. This annotation will review clinically relevant aspects of both forms of wetting and will concentrate on findings from paediatric urology, paediatric nephrology, genetics, endocrinology, child psychiatry, and epidemiology. Medical and technical terms are explained in the Glossary. Specific child psychological aspects will not be dealt with, as these have been excellently reviewed elsewhere, especially for nocturnal enuresis (Butler, 1987, 1994).

von Gontard's annotation (1998) on day- and night-wetting children takes a paediatric perspective on these prevalent and distressing conditions. This review addresses some of the major psychological issues relevant to nocturnal enuresis. Daytime wetting, which encapsulates a number of conditions each with separate aetiologies, distinct presentations, and specific treatment interventions, has been the focus of two recent reviews (Edens & Surwit, 1995; Robson, Leung, & Bloom, 1996) and will thus not be discussed in this annotation.