The measurement of obsessionality: first validation studies of the Lynfield obsessional/compulsive questionnaires.

The difficulties encountered in attempts at the rating and quantification of obsessional behaviour are outlined and some of the reasons for such difficulties are mentioned. The development of the Lynfield Obsessional-Compulsive Questionnaire from the Leyton Obsessional Inventory is discussed together with the advantages and disadvantages attendant upon its administration. The author concludes that the Lynfield Obsessional-Compulsive Questionnaire promises well as a measure for assessing change and that, following further validity and reliability tests, it may be used in multicentre trials of treatment procedures.