This is the fifth edition of a 1967 book originally authored by David Enoch, the late William Trethowan and John Barker. At the time, their collection of essays on unusual psychiatric phenomena was timely and it brought to the attention of psychiatrists and psychologists a range of bizarre beliefs and behaviours, some of which subsequently proved worthy of serious scientific consideration.

Uncommon Psychiatric Syndromes describes 11 so-called syndromes, each in its historical context and illustrated with detailed case examples. The latest edition also includes brief descriptions of a number of other syndromes that have so far not been included in any of the international classifications of psychiatric disorders.

In the preface to the new edition Enoch, who remains the first author, repeats his earlier assertion that the book has become ‘a classic’ that continues to be a ‘definitive source of information’ for ‘all practitioners in the field of mental health’. Unfortunately, despite his claim that it has been ‘fully updated’, the coverage of the relevant literature is disappointing at best and omits some of the most current theoretical discussions.

From the outset, Uncommon Psychiatric Syndromes advanced a psychodynamic framework for understanding these syndromes, epitomised by its treatment of the Capgras delusion in the first chapter. Despite trenchant criticisms that this sterile approach has yielded few insights and enabled little theoretical progression, it continues to be applied in an arbitrary post hoc fashion. A novelist may be forgiven these speculations but a scientist is required to provide proof, instead of ex cathedra assertions, that certain specific psychosocial factors are both necessary and sufficient for the development of the content of such delusions. In the century since the seminal reports by Capgras, a plethora of mutually incompatible psychodynamic explanations, reflecting the imaginations and conceptual frameworks of individual authors, have been invoked to account for his eponymous delusion. However, the psychotherapeutic process is intrinsically incapable of establishing the causal basis of psychopathology and any aetiological hypotheses generated during therapy are therefore of doubtful validity unless tested critically outside of this situation. Regrettably, Enoch et al do not provide any evidence at all.

The authors do allude to some neuropsychological and genetic work – perhaps excessively so in the chapter on Tourette syndrome, given the broad readership the book is intended for – but, by and large, their preference remains for the speculative and floridly psychodynamic rather than for more systematic, principled and predictive considerations. Regrettably, the cognitive neuropsychiatric approaches to the understanding of delusions, developed over the past two decades, are either overlooked or only cursorily incorporated in the text. As a result the scholarship is not systematic and because much relevant work has been overlooked it fails to consider alternative theoretical explanations to provide some sort of integration across the phenomena described.