A careful history is important, to ascertain if possible the nature of the thoughts and a clear account of the behaviours. The parents may underestimate how often the compulsive behaviours occur, and keeping a diary can be a very useful initial step. The obsessions in pure obsessive-compulsive disorder tend to be with contamination, dirt, germs, being neat and clean, fear of something going wrong, or hypochondriasis. The corresponding compulsions are mainly concerned with cleaning, washing or checking that things are all. Family factors may sometimes be relevant. For instance, a child may discover that his parents' response to his compulsive behaviour is the only time when they work together as parents. Children with obsessive-compulsive disorder should be referred sooner rather than later. Parents often come for help quite late in the development of the condition. Behavioural treatments are effective, particularly if combined with family therapy.