It has been argued that gene-by-environment interactions (G × E) research is unlikely to progress knowledge about psychiatric disorders, in contrast to genome-wide association (GWA) studies. However, G × E approaches are not alternatives for gene-hunting but a way to identify genetic and biological mechanisms within subgroups of patients exposed to a similar aetiological (environmental) factor via a process of ‘aetiological stratification’. This is important as diagnostic categories targeted by GWA studies are inherently heterogeneous and lack biological validity. Aetiological stratification builds on examining possible phenotypic and/or molecular specificity associated with exposure to the environmental factor across multiple potentially relevant disorders, combined with efforts to identify an underlying biological substrate. G × E hypotheses within this framework investigate (1) which genes influence the degree to which individuals develop identified biological alterations that link environmental exposure to specific phenotypic and/or molecular characteristics within or across psychiatric disorders and (2) which genes are implicated in determining the development of psychopathology once this biological alteration has been brought about. As gene-hunting is not a goal in itself, the examination of pathway and/or polygenic risk scores may be more informative than the examination of individual markers, at the same time reducing multiple testing and the associated risk of spurious findings.

There have been repeated calls to include mental health in the sustainable development goals (SDGs), arguing that progress in development will not be made without improvements in mental health. Although these calls are starting to gain political traction, currently only a tiny fraction of international development work includes mental health. A social determinants framework may be useful in incorporating mental health into sustainable development because it promotes a multi-sectorial and multi-disciplinary approach which is the corner stone of good development practice. Two approaches are suggested to make mental health a part of sustainable development: (1) integrate mental health into existing development programmes to promote social and economic environments that prevent mental health problems developing; (2) ensure that mental health programmes are better at promoting sustainable development by preventing the negative social and economic consequences of mental illness. Real-world examples of these approaches are provided. To achieve this, the mental health impact of wider development programmes, and the social and economic consequences of mental health interventions, must be evaluated. Development agencies should ensure that they have equity for mental health in all their policies, and investment must be increased for those mental health prevention, promotion and treatment programmes which have the greatest impact on sustainable development. The SDGs bring the promise of a more holistic approach to development. It is now the task of global mental health to demonstrate not just that mental health is an integral part of sustainable development, but that affordable and effective solutions exist which can improve mental health and development more broadly.

The revision effort leading to the publication of the fifth edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-5) was flawed in process, goals and outcome. The revision process suffered from lack of an adequate public record of the rationale for changes, thus shortchanging future scholarship. The goals, such as dimensionalising diagnosis, incorporating biomarkers and separating impairment from diagnosis, were ill-considered and mostly abandoned. However, DSM-5's greatest problem, and the target of the most vigorous and sustained criticism, was its failure to take seriously the false positives problem. By expanding diagnosis beyond plausible boundaries in ways inconsistent with DSM-5's own definition of disorder, DSM-5 threatened the validity of psychiatric research, including especially psychiatric epidemiology. I present four examples: increasing the symptom options while decreasing the diagnostic threshold for substance use disorder, elimination of the bereavement exclusion from major depression, allowing verbal arguments as evidence of intermittent explosive disorder and expanding attention-deficit/hyperactivity disorder to adults before addressing its manifest false positives problems.

René Descartes described the concept of mind–body dualism in the 16th century. This concept has been called his error but we prefer to call it his dogma because the error was recognised much later. We studied the original writings translated by various scholars. We believe that his dogma has caused tremendous amount of damage to Western psychiatry. This dualism has created boundaries between mind and body but as we know they are inextricably interlinked and influence each other. This has affected clinical practice and has increased the dichotomy between psychiatric services and the physical health care services in the West at least. This dualism has also contributed to stigma against mental illness, the mentally ill and the psychiatric services. We propose that it is time to abandon this mind–body dualism and to look at the whole patient and their illness experiences as is done in some other health care systems such as Ayurveda.

This paper introduces, describes and analyses the emerging concept of Global Mental Health (GMH). The birth of GMH can be traced to London, 2007, with the publication of a series of high-profile papers in The Lancet. Since then, GMH has developed into a movement with proponents, adherents, opponents, an ideology and core activities. The stated aims of the Movement for GMH are ‘to improve services for people living with mental health problems and psychosocial disabilities worldwide, especially in low- and middle-income countries where effective services are often scarce’. GMH could be considered an attempt to right a historic wrong. During the colonial and post-colonial eras, the mental health of subject populations was accorded a very low priority. This was fuelled by scientific racism, which alleged that mental illness was uncommon in places such as Africa. As developing nations have made the epidemiological transition, the burden of mental illness has proportionately increased, with research suggesting a massive ‘treatment gap’ between those in need and those actually receiving formal mental health care. As such, much GMH research and action has been devoted to: (i) the identification and scale-up of cost-effective evidence-supported interventions that could be made more widely available; (ii) task-shifting of such intervention delivery to mental-health trained non-specialist Lay Health Workers. GMH has come under sustained critique. Critics suggest that GMH is colonial medicine come full circle, involving the top-down imposition of Western psychiatric models and solutions by Western-educated elites. These critiques suggest that GMH ignores the various indigenous modalities of healing present in non-Western cultures, which may be psychologically adaptive and curative. Relatedly, critics argue that GMH could be an unwitting Trojan horse for the mass medicalisation of people in developing countries, paving the way for exploitation by Big Pharma, while ignoring social determinants of health.

The relationship between poverty and mental health is indisputable. However, to have an influence on the next set of sustainable global development goals, we need to understand the causal relationships between social determinants such as poverty, inequality, lack of education and unemployment; thereby clarifying which aspects of poverty are the key drivers of mental illness. Some of the major challenges identified by Lund (2014) in understanding the poverty–mental health relationship are discussed including: the need for appropriate poverty indicators; extending this research agenda to a broader range of mental health outcomes; the need to engage with theoretical concepts such as Amartya Sen's capability framework; and the need to integrate the concept of income/economic inequality into studies of poverty and mental health. Although income inequality is a powerful driver of poor physical and mental health outcomes, it features rarely in research and discourse on social determinants of mental health. This paper interrogates in detail the relationships between poverty, income inequality and mental health, specifically: the role of income inequality as a mediator of the poverty–mental health relationship; the relative utility of commonly used income inequality metrics; and the likely mechanisms underlying the impact of inequality on mental health, including direct stress due to the setting up of social comparisons as well as the erosion of social capital leading to social fragmentation. Finally, we need to interrogate the upstream political, social and economic causes of inequality itself, since these should also become potential targets in efforts to promote sustainable development goals and improve population (mental) health. In particular, neoliberal (market-oriented) political doctrines lead to both increased income inequality and reduced social cohesion. In conclusion, understanding the relationships between politics, poverty, inequality and mental health outcomes requires us to develop a robust, evidence-based ‘political economy of mental health.’

G × E in psychiatry may explain why environmental risk factors have big impact in some individuals but not in others, and conversely why relatives that are genetically at risk for disease do not all develop disease. Here we discuss two novel methods that use an aggregate genome-wide measure of genetic risk to detect G × E and estimate its effect in the population using data currently available and data we anticipate will be available in the near future. The first method exploits summary statistics from large-scale genome-wide association studies ignorant of the environmental conditions and detects G × E in an out-of-sample risk-profiling framework. The second method relies on larger samples and is based on a mixed linear model framework. It estimates variance explained directly from single nucleotide polymorphisms and environmental measures. Both methods have great potential to improve public health interventions focusing on risk-based screening that is informed by both genetic and environmental risk factors.

Recurring arguments in the media campaign preceding and following the publication of the DSM-5 have been that the manual, referred to as ‘the bible of psychiatry’, mislabels many people who are basically normal, and that the diagnostic categories it contains are invalid, not being based on laboratory tests. We present data on the use of the DSM worldwide, and discuss the need to assess systematically the pros and cons of operational and prototype approaches to psychiatric diagnosis. We consider different views about what qualifies as mental disorder and how the boundary between pathology and normality should be fixed. We review the role of laboratory tests as applied in medicine, emphasising that most of them are probabilistic, not pathognomonic, markers of disease. We finally summarise the promise and limitations of the Research Domain Criteria project, aiming to ‘transform psychiatric diagnosis’ by replacing descriptive psychopathology with behavioural and neurobiological measures.

Mainstream psychiatry emphasises controlling symptoms by taking medications. This approach ignores the role of context in shaping illness experiences and how people engage with mental health professionals. The focus on symptom control and medication management also narrows the function of the psychiatrist. This editorial argues that knowledge of patients’ lives is important for providing empathic care that is oriented to the outcomes that matter to patients. In addition, care that attends to the person-in-context motivates and sustains mental health providers by putting meaning back into medicine. Truly patient-centred care demands pushing back against the reductionism of contemporary psychiatry to thoughtfully engage with the complexities of patients’ lives.

The significant decline in the number of psychiatric hospital beds for more than two decades across Europe has changed the landscape of mental health services. This has rekindled debates about bed shortages and the reasons for variations in the number of inpatient beds, admissions to hospital and length of stay. Analysis of European Union (EU) level data shows that the UK has a relatively low number of admissions to hospital, yet a much higher than average length of stay compared with 12 other EU Member States. Understanding this is difficult, but recent studies shed some further light on the patterns and predictors of admissions and length of stay.

Two different and seemingly competing views on the diagnosis of major depressive disorder (MDD) exist. The first is that the diagnosis conflates adaptive sadness reactions with pathological states of depressed mood and that MDD is overdiagnosed and overtreated. The second is that MDD is an underdiagnosed and undertreated disorder, and one that is best characterised by a severe, chronic, recurrent or treatment-resistant course. Existing research suggests that both views are valid and merit being integrated. Anywhere from 30 to 50% of individuals will meet criteria for MDD at some point in their life. About half of these episodes are of brief duration and unlikely to recur. However, a remaining half is either chronic or recurrent. Data on the outpatient diagnosis of depression support the view that depression is simultaneously underdiagnosed and undertreated as well as overdiagnosed and overtreated. About one-third of the patients who meet criteria for MDD and receive placebos experience clinically significant and long-lasting improvement. Many other patients, however, are unresponsive to one or multiple active treatments. Thus, the diagnosis of MDD likely applies to individuals who are experiencing either normal periods of sadness or single-episode afflictions that are mild, unlikely to recur, and are placebo responsive, as well as to individuals with more severe clinical profiles. More research is needed that can help ascertain what contextual or biopsychological variables help distinguish between individuals who may be experiencing adaptive states of negative affect and those who experience severe, chronic, recurrent or treatment-resistant depressions.