Case formulation is an individualized process that seeks to understand the nature, sources, maintaining factors and alleviation factors for people's dif®culties (Eells, 2007; Tarrier, 2006). Many therapists recognize that case formulation needs to be embedded within the person's past and current context and should be based on an understanding of the functions of that person's emotions, behaviour and thoughts (Cullen & Combes, 2006). Two people may take an overdoseÐone was depressed, the other drunk and lost count of the painkillers taken for a hangover. The meaning of a depression in someone who, on the surface at least, appears to have a relatively good marriage and job is quite different from a depression in the context of poverty and domestic violence or previous child sexual abuse. Even though both people may have similar symptoms and beliefs of ``being weak and a failure'' when depressed, their beliefs may have very different origins and functions.