This publication brings together five chapters from 'Disease Control Priorities in Developing Countries' (2nd ed. , 2006) (ISBN 9780821361795) along with an introduction and a conclusion by WHO. The chapters cover mental disorders, neurological disorders, learning and developmental disabilities, and alcohol and illicit opiate abuse. It considers the cost-effectiveness of interventions for these specific groups of disorders, with the aim of contributing to the reformulation of policies and programmes and the reallocation of resources, eventually leading to reduction of morbidity and mortality.