Introduction

This book has had two main purposes. The first has been to gather together what we know about delusional disorder, to try to put it into some kind of systematic and understandable order, and then dare the reader to improve upon it. The second is to hammer home the point that this is a very real illness which causes a great deal of suffering and to insist that it is an onus on every psychiatrist to be able to diagnose it properly and treat it adequately.

With reference to the two quotations at the beginning of this chapter: much of our past knowledge on delusional disorder is little more than dogma and our current information is still so flimsy that any conclusions we draw from it can only be seen as ephemeral – to be challenged by new data as they appear. It is hoped that potential researchers in the field of delusional disorder will not be discouraged by the backward state of our knowledge and will keep Mary Queen of Scots' motto in mind: ‘In my end is my beginning.’

Delusional disorder lay rusting for a very long time and missed out on almost half a century of psychiatric progress.