Pimavanserin, a novel agent approved for the treatment of Parkinson’s disease psychosis, has potent actions as an antagonist/inverse agonist at serotonin 5HT2A receptors and less potent antagonist/inverse agonist actions at 5HT2C receptors.

The two main diagnostic systems, the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM), have undergone a number of revisions since their first editions: whereas the fifth edition of the DSM has been published in 2013, the eleventh revision of the ICD is expected by 2018. Although the process of harmonization between the 2 systems is still a debated topic, the forthcoming revision of the ICD is seemingly converging toward the DSM approach in regard to the reclassification of a number of disorders. Nevertheless, the 2 systems still exhibit considerable differences, partly due to their different purposes, development and revision processes, and target audiences. Furthermore, while alternative and innovative classification approaches are emerging with the aim of integrating the latest findings from neuroscience and genomics, both the DSM and ICD still fail to incorporate core concepts such as the clinical staging of psychiatric disorders and “neuroprogression,” as well as an adequate consideration of endophenotypes.

One of the main changes in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) was the separation of Stress Related Disorders from the Anxiety chapter. This separation paves the way to examine the unique characteristics of posttraumatic stress disorder (PTSD) (ie, identifiable onset, memory processes, etc) and related neural mechanisms. The time that elapses between the traumatic event and the manifestation of the disorder may also be addressed as the “golden hours,” or the window of opportunity in which critical processes take place and relevant interventions may be administrated.

Two widely used diagnostic systems, the International Statistical Classification of Diseases and Related Health Problems (ICD-10) and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), are reviewed for their ability to define those who will benefit from active treatment rather than placebo. Both systems suffer from a weakness in defining symptoms sufficiently clearly to separate depression from normal mood variations in the general population. Consequently, normal individuals may be medicalized and defined as suffering from and treated for depression. Also, in mild depression, unlike moderate depression, a lack of significant separation of active treatment from placebo has been shown in individual double-blind, placebo-controlled studies and in meta-analyses of these treatment studies. Both systems would be more useful for treatment purposes if they provided a clearer symptomatic definition of moderate depression, as is widely used in pivotal regulatory standard efficacy studies.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) categorization of mental disorders places “separation anxiety disorder” within the broad group of anxiety disorders, and its diagnosis no longer rests on establishing an onset during childhood or adolescence. In previous editions of DSM, it was included within the disorders usually first diagnosed in infancy, childhood, or adolescence, with the requirement for an onset of symptoms before the age of 18 years: symptomatic adults could only receive a retrospective diagnosis, based on establishing this early onset. The new position of separation anxiety disorder is based upon the findings of epidemiological studies that revealed the unexpectedly high prevalence of the condition in adults, often in individuals with an onset of symptoms after the teenage years; its prominent place within the DSM-5 group of anxiety disorders should encourage further research into its epidemiology, etiology, and treatment. This review examines the clinical features and boundaries of the condition, and offers guidance on how it can be distinguished from other anxiety disorders and other mental disorders in which “separation anxiety” may be apparent.

Neurodevelopmental disorders, specifically autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have undergone considerable diagnostic evolution in the past decade. In the United States, the current system in place is the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), whereas worldwide, the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) serves as a general medical system. This review will examine the differences in neurodevelopmental disorders between these two systems. First, we will review the important revisions made from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) to the DSM-5, with respect to ASD and ADHD. Next, we will cover the similarities and differences between ASD and ADHD classification in the DSM-5 and the ICD-10, and how these differences may have an effect on neurodevelopmental disorder diagnostics and classification. By examining the changes made for the DSM-5 in 2013, and critiquing the current ICD-10 system, we can help to anticipate and advise on the upcoming ICD-11, due to come online in 2017. Overall, this review serves to highlight the importance of progress towards complementary diagnostic classification systems, keeping in mind the difference in tradition and purpose of the DSM and the ICD, and that these systems are dynamic and changing as more is learned about neurodevelopmental disorders and their underlying etiology. Finally this review will discuss alternative diagnostic approaches, such as the Research Domain Criteria (RDoC) initiative, which links symptom domains to underlying biological and neurological mechanisms. The incorporation of new diagnostic directions could have a great effect on treatment development and insurance coverage for neurodevelopmental disorders worldwide.

While considerable efforts have been made to understand the neurobiological basis of substance addiction, the potentially “addictive” qualities of repetitive behaviors, and whether such behaviors constitute “behavioral addictions,” is relatively neglected. It has been suggested that some conditions, such as gambling disorder, compulsive stealing, compulsive buying, compulsive sexual behavior, and problem Internet use, have phenomenological and neurobiological parallels with substance use disorders. This review considers how the issue of “behavioral addictions” has been handled by latest revisions of the Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Classification of Diseases (ICD), leading to somewhat divergent approaches. We also consider key areas for future research in order to address optimal diagnostic classification and treatments for such repetitive, debilitating behaviors.

Twenty years have passed from the International Classification of Diseases, Tenth Revision (ICD-10) to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and, in the meanwhile, a lot of research data about eating disorders has been published. This article reviews the main modifications to the classification of eating disorders reported in the “Feeding and Eating Disorders” chapter of the DSM-5, and compares them with the ICD-10 diagnostic guidelines. Particularly, we will show that DSM-5 criteria widened the diagnoses of anorexia and bulimia nervosa to less severe forms (so decreasing the frequency of Eating Disorders, Not Otherwise Specified (EDNOS) diagnoses), introduced the new category of Binge Eating Disorder, and incorporated several feeding disorders that were first diagnosed in infancy, childhood, or adolescence. On the whole, the DSM-5 revision should allow the clinician to make more reliable and timely diagnoses for eating disorders.

The Diagnostic and Statistical of Mental Disorders, Fifth Edition (DSM-5) somatic symptom and related disorders chapter has a limited clinical utility. In addition to the problems that the single diagnostic rubrics and the deletion of the diagnosis of hypochondriasis entail, there are 2 major ambiguities: (1) the use of the term “somatic symptoms” reflects an ill-defined concept of somatization and (2) abnormal illness behavior is included in all diagnostic rubrics, but it is never conceptually defined. In the present review of the literature, we will attempt to approach the clinical issue from a different angle, by introducing the trans-diagnostic viewpoint of illness behavior and propose an alternative clinimetric classification system, based on the Diagnostic Criteria for Psychosomatic Research.

Bipolar disorders are a group of psychiatric disorders with profound negative impact on affected patients. Even if their symptomatology has long been recognized, diagnostic criteria have changed over time and diagnosis often remains difficult. The Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), issued in May 2013, comprises several changes regarding the diagnosis of bipolar disorders compared to the previous edition. Diagnostic categories and criteria for bipolar disorders show some concordance with the internationally also widely used Tenth Edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-10). However, there are also major differences that are worth highlighting. The aim of the following text is to depict and discuss those.

Obsessive-compulsive disorder (OCD) has been recognized as mainly characterized by compulsivity rather than anxiety and, therefore, was removed from the anxiety disorders chapter and given its own in both the American Psychiatric Association (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the Beta Draft Version of the 11th revision of the World Health Organization (WHO) International Classification of Diseases (ICD-11). This revised clustering is based on increasing evidence of common affected neurocircuits between disorders, differently from previous classification systems based on interrater agreement. In this article, we focus on the classification of obsessive-compulsive and related disorders (OCRDs), examining the differences in approach adopted by these 2 nosological systems, with particular attention to the proposed changes in the forthcoming ICD-11. At this stage, notable differences in the ICD classification are emerging from the previous revision, apparently converging toward a reformulation of OCRDs that is closer to the DSM-5.

Much has changed since the two dominant mental health nosological systems, the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM), were first published in 1900 and 1952, respectively. Despite numerous modifications to stay up to date with scientific and cultural changes (eg, exclusion of homosexuality as a disorder) and to improve the cultural sensitivity of psychiatric diagnoses, the ICD and DSM have only recently renewed attempts at harmonization. Previous nosological iterations demonstrate the oscillation in the importance placed on the biological focus, highlighting the tension between a gender- and culture-free nosology (solely biological) and a contextually relevant understanding of mental illness. In light of the release of the DSM 5, future nosological systems, such as the ICD 11, scheduled for release in 2017, and the Research Development Criteria (RDoC), can learn from history and apply critiques. This article aims to critically consider gender and culture in previous editions of the ICD and DSM to inform forthcoming classifications.

One of the most exciting psychiatric conditions is the bizarre psychomotor syndrome called catatonia, which may present with a large number of different motor signs and even vegetative instability. Catatonia is potentially life threatening. The use of benzodiazepines and electroconvulsive therapy (ECT) has been efficient in the majority of patients. The rich clinical literature of the past has attempted to capture the nature of catatonia. But the lack of diagnostic clarity and operationalization has hampered research on catatonia for a long time. Within the last decades, it became clear that catatonia had to be separated from schizophrenia, which was finally accomplished in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). In DSM-5, catatonia syndrome may be diagnosed as a specifier to major mood disorders, psychotic disorders, general medical conditions, and as catatonia not otherwise specified. This allows diagnosing the syndrome in a large variety of psychiatric disorders. Currently, the pathobiology remains widely unknown. Suspected neurotransmitter systems include gamma-aminobutyric acid (GABA) and glutamate. Neuroimaging reports pointed to reduced resting state activity and reduced task activation in motor areas of the frontal and parietal cortex. The new classification of catatonia will foster more clinical research and neuroscientific approaches by testing catatonia in various populations and applying stringent criteria. The scarce number of prospective trials will hopefully increase, as more trials will be encouraged within a more precise concept of catatonia.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) was published by the American Psychiatric Association (APA) in 2013, and the Work Group on the Classification of Psychotic disorders (WGPD), installed by the World Health Organization (WHO), is expected to publish the new chapter about schizophrenia and other primary psychotic disorders in 2017. We reviewed the available literature to summarize the major changes, innovations, and developments of both manuals. If available and possible, we outline the theoretical background behind these changes. Due to the fact that the development of ICD-11 has not yet been completed, the details about ICD-11 are still proposals under ongoing revision. In this ongoing process, they may be revised and therefore have to be seen as proposals. DSM-5 has eliminated schizophrenia subtypes and replaced them with a dimensional approach based on symptom assessments. ICD-11 will most likely go in a similar direction, as both manuals are planned to be more harmonized, although some differences will remain in details and the conceptual orientation. Next to these modifications, ICD-11 will provide a transsectional diagnostic criterion for schizoaffective disorders and a reorganization of acute and transient psychotic and delusional disorders. In this manuscript, we will compare the 2 classification systems.