One night while on call, I admitted a 90-year-old woman from a nursing home who had taken a fall. Although frail and a little confused, she seemed otherwise healthy, talking with me and smiling as I introduced myself and examined her. Stepping out of the room to answer a page, I returned to her querulous "Who are you?" When I replied, "I'm Doctor Brower," she said, "No, you're not." Peering at me, she continued. "You're not real." She reached up, pinched my cheek, and declared, "You're made of plastic."

This "delirium" seemed different, as a head CT scan showing bifrontal subdural hematomas soon confirmed. I had just encountered my first case of Capgras syndrome.

I found myself recalling that patient as I read through this cogent volume of chapter-length reviews covering a panoply of difficult diagnoses and unusual presentations of psychiatric ills. Capgras and other misidentification syndromes, delusional disorders, reactive psychoses, paraphrenia, folie à deux, de Clérambault's erotomania, and a host of other psychiatric outcasts populate the pages of this book with a liveliness rarely seen in psychiatric writing these days. For the clinician struggling to understand and treat patients who fail to fit the usual diagnostic categories, Troublesome Disguises provides wise instruction in the virtue of entertaining doubts, as well as practical advice for the assessment and management of atypical cases.

Drs. Bhugra and Munro generally deliver on their stated goal of providing both a theoretical and a practical guide, but they also have a larger aim: "We urge our readers to regard this book as an exercise in consciousness-raising as well as a warning to beware of diagnostic systems which, despite their many virtues, may become too influential and may perpetuate errors which are to the detriment of our patients."

While giving due credit to the reigning diagnostic systems for encouraging coherence, uniformity, and a diagnostic lingua franca, the editors criticize the current manuals for their pervasive "American outlook," the tendency to reduce diagnosis to cookbook formulas, and endless expansion of residual categories to accommodate "atypical" patients who defy the official labels. In response, their book takes "the rather iconoclastic approach that ICD-10 and DSM-IV are not the founts of all wisdom in psychiatry and that they often overlook certain groups of illnesses which have a valid existence and which are in danger of becoming obscure because they are not officially recognized."

Like many iconoclasts, the editors and their contributors invoke the virtues of a purer past, predating the current idols they seek to rock. The often elegant writing and sometimes arch tone that characterize the text hark back to an older, literary style, as befits these British or U.K.-trained authors. With their frequent tributes to the phenomenologic diagnostic tradition of Kraepelin and Jaspers, these contemporary researchers and clinicians demonstrate a sense of history rare in psychiatric scientific discourse today. In the process of refreshing our curiosity about some long-standing diagnostic controversies and conundrums, they repeatedly draw us to explore anew the boundaries that presently demarcate our diagnoses and disciplines.

One such boundary lies at the interface between psychiatry and neurology. As the chapters on "Misidentification Syndromes," "Paranoia or Delusional Disorder," "Pseudoseizures: A Semantic and Clinical Muddle," and "Atypical Illnesses" highlight, unusual disorders and presentations often travel with medical and neurologic illness, and their diagnosis and treatment frequently demand an integrative, neuropsychiatric approach.

The contribution on "Factitious Disorders" also focuses on diagnoses that blur the line between psyche and soma. The apparent rarity or infrequency of diagnosis of some conditions, as the chapters on "Paraphilias" and "Disorders of Passion" point out, may follow on the fact that their sufferers often present in settings where psychiatry shares a border with other specialties and institutions—for example, the erotomanic stalker who appears in court, or the fetishist who comes to a clinic for sexual dysfunction.

The chapter on "FolieàDeux" reminds clinicians steeped in the lore of neurobiology that a delusion with a presumed biochemical basis can, under the right conditions, prove contagious across the divide between one brain and another. Similarly, the contribution on "Reactive Psychoses" challenges distinctions currently taken for granted between conditions related to stressful events (for example, adjustment disorders and some depressive episodes), and those arising independently, based on biochemical dysfunction within the brain (for example, mania and most psychotic disorders).

In the chapter on reactive psychoses, Ungvari and Mullen carefully lay out the historical and research evidence for brief, self-limited psychotic episodes whose onset and content relate to life events. While noting that patients who present with the condition likely have biologic and psychosocial vulnerabilities, the authors resurrect the largely discarded concept that psychotic processes may mark one extreme of a spectrum from psychic integration to disintegration. They urge that successful diagnosis and treatment of reactive psychosis may depend on the clinician's making the effort to understand the connection between the psychotic content and the precipitating events, though they lament that managed care systems generally do not allow the time for such exploratory work.

Surprisingly, the book overlooks one particularly vexing disguise: the psychiatric presentations of seizure disorders. The psychiatric complications of epilepsy, which may include mood, anxiety, and psychotic conditions, have significance both for the history of psychiatry and for the most current developments in neuropsychiatry. Although the assertion of a causal relationship between seizure disorders and comorbid psychiatric diagnoses remains controversial, such conditions often appear in atypical guise. Michael Trimble, who contributes the related chapter on pseudoseizures, is a leading authority in the psychiatry of epilepsy. Perhaps the editors concluded that a fuller treatment of epilepsy and other neuropsychiatric disorders would overwhelm the scope of this book.

"Culture-Bound Syndromes" is the final chapter of Troublesome Disguises. Bhugra and Jacob's overview of such phenomena as amok, ataque de nervios, and koro strikes an apt final note. The authors observe that rather than being foreign exotica, "culture-bound" syndromes may also include such DSM staples as eating disorders and impulse control disorders. (It is hard to imagine a starving denizen of the developing world running up a credit-card account buying food and then refusing to eat the proceeds.) A proper understanding of the relationship between culture and mental illness, the authors rightly point out, would recognize that for both sufferers and witnesses, doctors and patients, psychiatric disorders—indeed, all illnesses—have individual, social, economic, and political significance. In short, symptoms have meaning. In the present age, few ideas could be more iconoclastic.

This perspective set me to thinking about my own training in psychiatry and the ways in which diagnostic orthodoxy may have blinded me to my patients who had conditions discussed in this book. I caught the case of Capgras syndrome, but I missed the elderly woman with paraphrenia and the young software engineer with delusional disorder.

Dr. Brower is a law and psychiatry fellow at the University of Massachusetts Medical Center in Worcester and Worcester State Hospital.