This book addresses the issue of comorbid conditions in schizophrenia and has a two-fold aim. The first is relevant to the clinical practice of psychiatry and consists in pointing out the importance of recognizing and assessing symptoms and syndromes that, even though not directly related to the “core” clinical features of schizophrenia, may complicate the course and the long-term management of the disease. Comorbid obsessive-compulsive, panic, and depressive symptoms are examples of these conditions.

The second aim of the volume is more theoretical. It consists in challenging the view of schizophrenia as a homogenous and unitary category and proposing a more realistic, dimensional approach to the disease. According to the classical hierarchical/categorical approach, the occurrence of depressive or anxiety symptoms in an individual with schizophrenia and pervasive paranoid ideation is usually viewed as the obvious and direct consequence of the psychotic symptoms, and the condition is treated according to this perspective. However, this approach does not provide any explanation about the reasons why only some, and not all, paranoid patients develop anxiety or depressive symptoms.

The chapter authors suggest that patients with schizophrenia and comorbid conditions should be considered in the context of the disease’s heterogeneity and managed on the basis of their individual and peculiar clinical characteristics.

Several well-recognized experts provide an exhaustive overview in the chapters on the comorbid psychiatric conditions frequently associated with schizophrenia. Siris discusses the co-occurrence of depression and schizophrenia. Depressive symptoms during the course of schizophrenia are probably the most frequently observed in clinical practice, and several lines of evidence underline the need for careful assessment and management for their possible implications (e.g., higher risk of suicide attempts).

In chapter 3, Hwang and associates address the problem of comorbid obsessive-compulsive disorder (OCD) in schizophrenia. The prevalence of the phenomenon (1% to 6% of patients with schizophrenia have comorbid OCD symptoms during the course of their illness) is quite high and deserves careful assessment, particularly when the obsessive symptoms overlap with delusional phenomena, leading to a complex and difficult-to-disentangle clinical picture. The authors focus on the relative onset of the two phenomena and identify three groups of patients with schizophrenia and OCD—i.e., those whose OCD symptoms preceded the onset of schizophrenia, those with simultaneous onsets of schizophrenia and OCD, and those whose OCD symptoms developed after the onset of schizophrenia. These three groups show clear differences in clinical course, but overall their outcome is worse than that of patients with schizophrenia who do not have comorbid OCD. The problems related to treatment management are also discussed. For example, the addition of a serotonergic antidepressant with antiobsessional activity may interfere with the antipsychotic treatment.

Other clinical features that may occur in a patient with schizophrenia and complicate the course of the illness are panic symptoms (chapter 4 by Pitch and associates), aggression and violence (chapter 8 by Citrome and Volavka), and substance abuse (chapter 9 by Ziedonis and Nickou). The presentation of case vignettes in this book is very useful and helps the reader understand the complexity of the conditions discussed. The vignettes provide examples of the practical clinical management of patients with schizophrenia and comorbid conditions.

Additional chapters complete the overview of comorbid conditions that can complicate the course of schizophrenia, such as medical and surgical conditions and pregnancy (chapters 5 and 6 by Gilmore and associates).

In conclusion, Schizophrenia and Comorbid Conditions is a very useful tool for both clinical psychiatrists and researchers in the field. Particularly valuable is the fact that the book points out and supports with a good review of the literature and clinical examples that schizophrenia is a heterogeneous condition and that treatment management should be individualized for each patient. The evidence for the concept that a subclassification of schizophrenia on the basis of comorbid conditions will lead to a significantly better outcome of the illness (and better treatment strategies) is still controversial. Symptoms like anxiety and depression, even though clinically relevant, may be not specific but represent epiphenomena of a cognitive and affective disruption caused by the core psychotic symptoms. However, these symptoms need careful clinical assessment and specific clinical interventions. In this context and in the view of future efforts toward a better understanding of the complex phenomenology of schizophrenia, this volume provides a valuable contribution to the field.