Eating disorders are historically underserved in healthcare, but are increasingly prevalent and recognised for their high costs regarding mortality, quality of life and the economy. Those with longstanding eating disorders are commonly labelled ‘severe and enduring’ (SEED), which has been challenged for its conceptual vagueness and potential to discourage patients. Attempts to define individuals from this cohort as having ‘terminal’ illness have also gained traction in recent years. This paper is grounded in lived/living experience and relevant research. It challenges the logical coherence and utility of SEED, arguing that the word ‘enduring’ unhelpfully situates intractability of longstanding illness within patients themselves and the nature of their illness. This risks a sense of inevitability and overlooks the important role of contextual factors such as lacking resources and insufficient evidence for withholding active treatment. Recommendations suggest approaches to dismantling unhelpful binaries between early intervention and intensive support, recovery and decline.

Traditionally, psychopathology has been classified based on the publications of authoritative bodies, such as the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (APA’s DSM). Recently, researchers have expressed an interest in basing classification more on data, as opposed to authority. This movement led to the formation of the Hierarchical Taxonomy of Psychopathology (HiTOP) consortium. Working from data, the HiTOP approach emphasizes dimensions of human individual differences that are arranged hierarchically, as opposed to categories that are arranged based on traditional DSM chapter rubrics. In this talk, I will describe the origins and status of the HiTOP approach, as well as current and future HiTOP directions and priorities.

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.

Perlson et al's editorial ‘Envisioning a future for transgender and gender-diverse people beyond the DSM’ heralds the arrival of the ICD-11's gender incongruence categories among conditions related to sexual health, brightening the spotlight on the re- (or rather de-)classification of gender-related disorders, which is a step in the right direction.

Adults with neurodevelopmental disorders frequently present to, but fit uneasily into, adult mental health services. We offer definitions of important terms related to neurodevelopmental disorders through unifying research data, medical and other viewpoints. This may improve understanding, clinical practice and development of neurodevelopmental disorder pathways within adult mental health services.

Many mental disorders are linked to personality, but this is rarely recognised in clinical practice. It is suggested here that when the links are very close, the two can be joined. Galenic syndromes are so named because Galen was the first physician to recognise the links between personality and disease.

The transition from DSM-IV to DSM-5 relaxed diagnostic criteria for anorexia nervosa and bulimia nervosa, and recognised a third eating disorder, binge eating disorder. However, a large proportion of cases remain in the ill-defined category of ‘other specified feeding and eating disorders’. We sought to investigate the utility of a proposed solution to classify this group further, subdividing based on the dominant clinical feature: binge eating/purging or restraint. Cluster analysis failed to identify clusters in a treatment-seeking sample based on symptoms of restraint, binge eating, purging and over-evaluation of shape and weight. Further investigation of this highly heterogeneous group is required.

Genetic testing in psychiatry is becoming more common, but psychiatrists often receive little training in it. Given the pace of change in genetics, understanding the current methods of testing and their associated merits and limitations can therefore be challenging for some. This narrative, written for psychiatrists in the clinic, aims to cut through the jargon and describe current genetic testing techniques and their evolution from previous methods. It discusses benefits and risks of testing, how geneticists decide whether genetic variants are pathogenic, terminology found in genetic test results and how best to support patients with genetic diagnoses. It also describes methods used to study the genetics of polygenic disorders. It is anticipated this will facilitate a greater understanding of genetic testing and promote confidence among psychiatrists to discuss its clinical utility and implications with patients.

The question of ‘what is a mental disorder?’ is central to the philosophy of psychiatry, and has crucial practical implications for psychiatric nosology. Rather than approaching the problem in terms of abstractions, we review a series of exemplars – real-world examples of problematic cases that emerged during work on and immediately after DSM-5, with the aim of developing practical guidelines for addressing future proposals. We consider cases where (1) there is harm but no clear dysfunction, (2) there is dysfunction but no clear harm, and (3) there is possible dysfunction and/or harm, but this is controversial for various reasons. We found no specific criteria to determine whether future proposals for new entities should be accepted or rejected; any such proposal will need to be assessed on its particular merits, using practical judgment. Nevertheless, several suggestions for the field emerged. First, while harm is useful for defining mental disorder, some proposed entities may require careful consideration of individual v. societal harm, as well as of societal accommodation. Second, while dysfunction is useful for defining mental disorder, the field would benefit from more sharply defined indicators of dysfunction. Third, it would be useful to incorporate evidence of diagnostic validity and clinical utility into the definition of mental disorder, and to further clarify the type and extent of data needed to support such judgments.

Subthreshold post-traumatic stress disorder (PTSD) is more prevalent than PTSD, yet its role as a potential risk factor for PTSD is unknown. To address this gap, we analysed data from a 7-year, prospective national cohort of USA veterans. Of veterans with subthreshold PTSD at wave 1, 34.3% developed PTSD compared with 7.6% of trauma-exposed veterans without subthreshold PTSD (relative risk ratio 6.4). Among veterans with subthreshold PTSD, specific PTSD symptoms, greater age, cognitive difficulties, lower dispositional optimism and new-onset traumas predicted incident PTSD. Results suggest that preventive interventions targeting subthreshold PTSD and associated factors may help mitigate risk for PTSD in USA veterans.