The paper discusses the psychotherapy of an adolescent who, during a psychotic breakdown, developed a mystical delusion on a religious theme. Splitting processes and the narcissistic defences that accompany them are illustrated. After showing how the patient had recourse to splitting and how the split-off parts of the ego took refuge inside an internal object, the ego's efforts to make contact once more with these split-off aspects and to reintegrate them are highlighted. With the help of certain concepts developed by, for example, Rosenfeld and Meltzer — specifically those relating to the organization of internal groupings or ‘gangs’ and their destructiveness and the compartmentalization of internal objects — the author shows how certain particularities of the patient's internal world can be understood in terms of these splitting processes. In addition the clinical material presented raises several technical questions, in particular those relating to dissociative processes and delusion or delusional theories as they become manifest in the treatment.