Sir, regarding the letter Fabricated illness (BDJ 2009; 206: 239) we agree with much of what the author says. However, professionals commonly make the mistake of believing they must diagnose non-accidental injury whereas in fact their role is much more straightforward. When assessing a child's injury healthcare professionals should raise the alarm where the history of events does not match the clinical presentation or where there is a delay in presentation to services. In addition the author refers to factitious disorder but then goes on to describe factitious disorder by proxy. Factitious disorder by proxy is the intentional production or feigning of physical or psychological signs or symptoms in another person who is under the individuals care. Factitious disorder by proxy has yet to be recognised as an official separate category in the DSM-IV. Appendix B of the DSM-IV lists the following research criteria for factitious disorder by proxy:

  • The motivation for the perpetrator's behaviour is to assume the sick role by proxy

  • External incentives for the behaviour (such as economic gain) are absent

  • The behaviour is not better accounted for by another mental disorder.

Symptoms should be attributed to this diagnosis with great caution and only in consultation with child psychiatry and paediatric colleagues.