Fifty Years of Psychiatric Classification and Epidemiology Interactions: What is a Mental Disorder?

Psychiatric clinical diagnostic formulation has evolved over time. The changes alter our understanding and our ability to provide a public health perspective on the epidemiology of mental disorders in large populations. Epidemiology is an important perspective and set of tools to assess prevalence, treated prevalence, untreated prevalence, individual risks for mental disorders, and possible links to the etiology of disorders by following the trails of environmental exposures, biological measures, interpersonal dynamics, and genetic risk factors. As communities develop health-care services to treat individuals with mental disorders, knowledge about their prevalence and treatment requirements is also important. Since severe mental disorders may require institutional care, the diagnostic criteria used may either protect an individual's liability for dangerous behavior (i.e. the insanity defense) or be used to control political and social dissidents. The criteria may also be used to determine evidence-based treatment options and eligibility for disability benefits. In this paper, using my vantage points as a physician scientist and public health officer, with leadership positions in national federal and professional mental health organizations, I address the developments in these areas over the past 50 years that have influenced institutional positions in the U.S. National Institute of Mental Health, the World Health Organization, the American Psychiatric Association, and the Center for the Study of Traumatic Stress. These perspectives may aid the next generation of investigators to advance the epidemiological and mental disorder classification scientific fields.

The Hierarchical Taxonomy of Psychopathology (HiTOP) in psychiatric practice and research.

The Hierarchical Taxonomy of Psychopathology (HiTOP) has emerged out of the quantitative approach to psychiatric nosology. This approach identifies psychopathology constructs based on patterns of co-variation among signs and symptoms. The initial HiTOP model, which was published in 2017, is based on a large literature that spans decades of research. HiTOP is a living model that undergoes revision as new data become available. Here we discuss advantages and practical considerations of using this system in psychiatric practice and research. We especially highlight limitations of HiTOP and ongoing efforts to address them. We describe differences and similarities between HiTOP and existing diagnostic systems. Next, we review the types of evidence that informed development of HiTOP, including populations in which it has been studied and data on its validity. The paper also describes how HiTOP can facilitate research on genetic and environmental causes of psychopathology as well as the search for neurobiologic mechanisms and novel treatments. Furthermore, we consider implications for public health programs and prevention of mental disorders. We also review data on clinical utility and illustrate clinical application of HiTOP. Importantly, the model is based on measures and practices that are already used widely in clinical settings. HiTOP offers a way to organize and formalize these techniques. This model already can contribute to progress in psychiatry and complement traditional nosologies. Moreover, HiTOP seeks to facilitate research on linkages between phenotypes and biological processes, which may enable construction of a system that encompasses both biomarkers and precise clinical description.

A Crosswalk Study of DSM-IV and DSM-5 Criteria for PTSD from the DSM-5 Field Trials.

Objective: Posttraumatic stress disorder (PTSD) is prevalent and sometimes severely disabling. Providing effective treatment for PTSD and addressing its social consequences require accurate diagnosis. PTSD criteria have changed in all editions of the American Diagnostic Criteria since introduction of the diagnosis in DSM-III in 1980. The DSM-5 Field Trials demonstrated very good inter-rater reliability for PTSD, but a crosswalk study comparing DSM-IV and DSM-5 criteria has potential to identify diagnostic differences generated by changed criteria. Methods: A DSM-IV to DSM-5 PTSD crosswalk study was conducted in real-world adult clinical treatment settings in two DSM-5 Field Trials sites, the Dallas (N = 93) and Houston (N = 48) Veterans Affairs medical centers. The crosswalk assessment was conducted by trained clinicians who interviewed the patients and rated both sets of criteria on a combined checklist. Results: PTSD prevalence differed insubstantially between criteria sets (42% vs. 45% and 55% vs. 52% in the Dallas and Houston sites, respectively), with moderate to excellent diagnostic agreement (reliability indicated, respectively, by κ = .53 and .93); however, substantial proportions of individuals diagnosed in one criteria set did not meet criteria in the other. Differences in cross-criteria diagnostic reliability were largely a function of differing definitions of criterion A trauma. Conclusions: Reliability across the two criteria sets was generally good to excellent, and diagnostic discrepancy predominantly reflected the elimination of criterion A2 in DSM-5 with a smaller contribution from changes to the avoidance and numbing criteria.

Les progrès dans la réalisation de la classification quantitative de la psychopathologie.

Shortcomings of approaches to classifying psychopathology based on expert consensus have given rise to contemporary efforts to classify psychopathology quantitatively. In this paper, we review progress in achieving a quantitative and empirical classification of psychopathology. A substantial empirical literature indicates that psychopathology is generally more dimensional than categorical. When the discreteness versus continuity of psychopathology is treated as a research question, as opposed to being decided as a matter of tradition, the evidence clearly supports the hypothesis of continuity. In addition, a related body of literature shows how psychopathology dimensions can be arranged in a hierarchy, ranging from very broad "spectrum level" dimensions, to specific and narrow clusters of symptoms. In this way, a quantitative approach solves the "problem of comorbidity" by explicitly modeling patterns of co-occurrence among signs and symptoms within a detailed and variegated hierarchy of dimensional concepts with direct clinical utility. Indeed, extensive evidence pertaining to the dimensional and hierarchical structure of psychopathology has led to the formation of the Hierarchical Taxonomy of Psychopathology (HiTOP) Consortium. This is a group of 70 investigators working together to study empirical classification of psychopathology. In this paper, we describe the aims and current foci of the HiTOP Consortium. These aims pertain to continued research on the empirical organization of psychopathology; the connection between personality and psychopathology; the utility of empirically based psychopathology constructs in both research and the clinic; and the development of novel and comprehensive models and corresponding assessment instruments for psychopathology constructs derived from an empirical approach.

Integrating the Hierarchical Taxonomy of Psychopathology (HiTOP) into clinical practice.

OBJECTIVE: Diagnosis is a cornerstone of clinical practice for mental health care providers, yet traditional diagnostic systems have well-known shortcomings, including inadequate reliability, high comorbidity, and marked within-diagnosis heterogeneity. The Hierarchical Taxonomy of Psychopathology (HiTOP) is a data-driven, hierarchically based alternative to traditional classifications that conceptualizes psychopathology as a set of dimensions organized into increasingly broad, transdiagnostic spectra. Prior work has shown that using a dimensional approach improves reliability and validity, but translating a model like HiTOP into a workable system that is useful for health care providers remains a major challenge. METHOD: The present work outlines the HiTOP model and describes the core principles to guide its integration into clinical practice. RESULTS: Potential advantages and limitations of the HiTOP model for clinical utility are reviewed, including with respect to case conceptualization and treatment planning. A HiTOP approach to practice is illustrated and contrasted with an approach based on traditional nosology. Common barriers to using HiTOP in real-world health care settings and solutions to these barriers are discussed. CONCLUSIONS: HiTOP represents a viable alternative to classifying mental illness that can be integrated into practice today, although research is needed to further establish its utility. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The Aspirations for a Paradigm Shift in DSM-5: An Oral History.

The initial plans for the DSM-5 revision envisioned a paradigm shift away from traditional diagnostic categories. However, plans for a major move from descriptive to etiologic diagnoses were quickly abandoned as infeasible. Support was much broader for adding dimensional/spectrum constructs to the categorical diagnoses, although this was interpreted in various ways. Delegation of substantial autonomy to work groups with modest central coordination was seen as problematic by some work groups and positively by others. Controversies emerged around the standards for diagnostic change, and the degree to which the same standards should be used across diagnostic groups. The Summit Group was given the final task of trying to forge a consensus among the various review groups. We conclude with thoughts about the difficulty of trying to revise an entire manual all at once and the desirability of developing clear rules for change at the outset of such a diagnostic project.

Progress in achieving quantitative classification of psychopathology.

Shortcomings of approaches to classifying psychopathology based on expert consensus have given rise to contemporary efforts to classify psychopathology quantitatively. In this paper, we review progress in achieving a quantitative and empirical classification of psychopathology. A substantial empirical literature indicates that psychopathology is generally more dimensional than categorical. When the discreteness versus continuity of psychopathology is treated as a research question, as opposed to being decided as a matter of tradition, the evidence clearly supports the hypothesis of continuity. In addition, a related body of literature shows how psychopathology dimensions can be arranged in a hierarchy, ranging from very broad "spectrum level" dimensions, to specific and narrow clusters of symptoms. In this way, a quantitative approach solves the "problem of comorbidity" by explicitly modeling patterns of co-occurrence among signs and symptoms within a detailed and variegated hierarchy of dimensional concepts with direct clinical utility. Indeed, extensive evidence pertaining to the dimensional and hierarchical structure of psychopathology has led to the formation of the Hierarchical Taxonomy of Psychopathology (HiTOP) Consortium. This is a group of 70 investigators working together to study empirical classification of psychopathology. In this paper, we describe the aims and current foci of the HiTOP Consortium. These aims pertain to continued research on the empirical organization of psychopathology; the connection between personality and psychopathology; the utility of empirically based psychopathology constructs in both research and the clinic; and the development of novel and comprehensive models and corresponding assessment instruments for psychopathology constructs derived from an empirical approach.

The Hierarchical Taxonomy of Psychopathology (HiTOP): A dimensional alternative to traditional nosologies.

The reliability and validity of traditional taxonomies are limited by arbitrary boundaries between psychopathology and normality, often unclear boundaries between disorders, frequent disorder co-occurrence, heterogeneity within disorders, and diagnostic instability. These taxonomies went beyond evidence available on the structure of psychopathology and were shaped by a variety of other considerations, which may explain the aforementioned shortcomings. The Hierarchical Taxonomy Of Psychopathology (HiTOP) model has emerged as a research effort to address these problems. It constructs psychopathological syndromes and their components/subtypes based on the observed covariation of symptoms, grouping related symptoms together and thus reducing heterogeneity. It also combines co-occurring syndromes into spectra, thereby mapping out comorbidity. Moreover, it characterizes these phenomena dimensionally, which addresses boundary problems and diagnostic instability. Here, we review the development of the HiTOP and the relevant evidence. The new classification already covers most forms of psychopathology. Dimensional measures have been developed to assess many of the identified components, syndromes, and spectra. Several domains of this model are ready for clinical and research applications. The HiTOP promises to improve research and clinical practice by addressing the aforementioned shortcomings of traditional nosologies. It also provides an effective way to summarize and convey information on risk factors, etiology, pathophysiology, phenomenology, illness course, and treatment response. This can greatly improve the utility of the diagnosis of mental disorders. The new classification remains a work in progress. However, it is developing rapidly and is poised to advance mental health research and care significantly as the relevant science matures. (PsycINFO Database Record

APIRE Practice Research Network: accomplishments, challenges, and lessons learned.

The Practice Research Network (PRN) was established in 1993 to bridge the gap between the science base and the clinical practice of psychiatry by expanding the generalizability of findings and involving clinicians in the development and conduct of research. It began as a nationwide network of psychiatrists and has evolved to conduct large-scale, clinical and policy research studies using randomly selected samples of psychiatrists from the AMA Physician Masterfile. This paper provides an overview of major PRN initiatives and the impact of these studies. It describes the benefits to clinicians of participating in PRN research, as well as strategies developed to address key challenges.

Feasibility and acceptability of the DSM-5 Field Trial procedures in the Johns Hopkins Community Psychiatry Programs.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) contains criteria for psychiatric diagnoses that reflect advances in the science and conceptualization of mental disorders and address the needs of clinicians. DSM-5 also recommends research on dimensional measures of cross-cutting symptoms and diagnostic severity, which are expected to better capture patients' experiences with mental disorders. Prior to its May 2013 release, the American Psychiatric Association (APA) conducted field trials to examine the feasibility, clinical utility, reliability, and where possible, the validity of proposed DSM-5 diagnostic criteria and dimensional measures. The methods and measures proposed for the DSM-5 field trials were pilot tested in adult and child/adolescent clinical samples, with the goal to identify and correct design and procedural problems with the proposed methods before resources were expended for the larger DSM-5 Field Trials. Results allowed for the refinement of the protocols, procedures, and measures, which facilitated recruitment, implementation, and completion of the DSM-5 Field Trials. These results highlight the benefits of pilot studies in planning large multisite studies.

Testing DSM-5 in routine clinical practice settings: feasibility and clinical utility.

OBJECTIVE: This article describes the clinical utility and feasibility of proposed DSM-5 criteria and measures as tested in the DSM-5 Field Trials in Routine Clinical Practice Settings (RCP). METHODS RCP data were collected online for six months (October 2011 to March 2012). Participants included psychiatrists, licensed clinical psychologists, clinical social workers, advanced practice psychiatric-mental health nurses, licensed counselors, and licensed marriage and family therapists. Clinicians received staged, online training and enrolled at least one patient. Patients completed self-assessments of cross-cutting symptom domains, disability measures, and an evaluation of these measures. Clinicians conducted diagnostic interviews and completed DSM-5 and related assessments and a clinical utility questionnaire. RESULTS: A total of 621 clinicians provided data for 1,269 patients. Large proportions of clinicians reported that the DSM-5 approach was generally very or extremely easy for assessment of both pediatric (51%) and adult (46%) patients and very or extremely useful in routine clinical practice for pediatric (48%) and adult (46%) patients. Clinicians considered the DSM-5 approach to be better (57%) or much better (18%) than that of DSM-IV. Patients, including children age 11 to 17 (47%), parents of children age six to ten (64%), parents of adolescents age 11 to 17 (72%), and adult patients (52%), reported that the cross-cutting measures would help their clinicians better understand their symptoms. Similar patterns in evaluations of feasibility and clinical utility were observed among clinicians from various disciplines. CONCLUSIONS: The DSM-5 approach was feasible and clinically useful in a wide range of routine practice settings and favorably received by both clinicians and patients.

Sustaining practice change one year after completion of the national depression management leadership initiative.

OBJECTIVE: This report describes the sustainability of quality improvement interventions for depression care in psychiatric practice one year after the completion of the National Depression Management Leadership Initiative (NDMLI) in 2006. The main intervention involved continued use of the nine-item depression scale of the Patient Health Questionnaire (PHQ-9) for routine care of patients with depressive disorders. METHODS: One year after project completion, lead psychiatrists from the 17 participating practices were surveyed about the sustainability of key practice interventions and dissemination of the interventions. RESULTS: All 14 practices that provided baseline and follow-up data reported sustained use of the PHQ-9 for screening, diagnosis, or monitoring purposes. Moreover, practices reported dissemination of this approach to clinicians within and outside their practices. CONCLUSIONS: Psychiatrists reported sustainability and dissemination of PHQ-9 use one year after the conclusion of the NDMLI. The model has potential as a depression care improvement strategy and is worthy of additional study.

The DSM-5: Classification and criteria changes.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) marks the first significant revision of the publication since the DSM-IV in 1994. Changes to the DSM were largely informed by advancements in neuroscience, clinical and public health need, and identified problems with the classification system and criteria put forth in the DSM-IV. Much of the decision-making was also driven by a desire to ensure better alignment with the International Classification of Diseases and its upcoming 11th edition (ICD-11). In this paper, we describe select revisions in the DSM-5, with an emphasis on changes projected to have the greatest clinical impact and those that demonstrate efforts to enhance international compatibility, including integration of cultural context with diagnostic criteria and changes that facilitate DSM-ICD harmonization. It is anticipated that this collaborative spirit between the American Psychiatric Association (APA) and the World Health Organization (WHO) will continue as the DSM-5 is updated further, bringing the field of psychiatry even closer to a singular, cohesive nosology.