To date there have been few peer-reviewed studies on the feasibility, acceptability and effectiveness of digital technologies for mental health promotion and disorder prevention. Any evaluation of these evolving technologies is complicated by a lack of understanding about the specific risks and possible benefits of the many forms of internet use on mental health. To adequately meet the mental health needs of today's society, psychiatry must engage in rigorous assessment of the impact of digital technologies.

This supplement outlines the development and piloting of district mental healthcare plans from five low- and middle-income countries, together with the methods for their design, evaluation and costing. In this editorial we consider the challenges that these programmes face, highlight their innovations and draw conclusions.

Mental health research funding priorities in high-income countries must balance longer-term investment in identifying neurobiological mechanisms of disease with shorter-term funding of novel prevention and treatment strategies to alleviate the current burden of mental illness. Prioritising one area of science over others risks reduced returns on the entire scientific portfolio.

This commentary takes up the notion proposed by Lewis-Fernández and colleagues that we need more balance in research priorities. Specifically, our reliance on neurobiology may be misplaced and likely to be unrewarding unless we ensure that: (a) research with better return for patients and the public is also pursued; (b) research findings are put into practice; and (c) we retain a focus on proportionate investment in service provision. Patient, public and economic perspectives should drive the decision making for better investment, and behaviour change might be better targeted at commissioners and policy makers rather than patients and providers.

The treatment of depression remains suboptimal, highlighting the need for more effective antidepressants. Traditional drug discovery and development is time-consuming and costly, prompting the need for faster translation of novel therapies into practice. But clinical expediency comes at a cost against which potential benefits need to be considered judiciously.

The pathogenesis of Alzheimer's disease is complex. The amyloid hypothesis has directed research efforts for many years, but it has recently been questioned after failed drug trials. Here, we review the evidence for and against and suggest that it might be premature to abandon the amyloid hypothesis.

Despite evidence for their comparable efficacy, psychotherapy faces a dramatic decline relative to pharmacotherapy in psychiatry. A deep ideological reason for this decline centres on the belief that psychotherapy is a psychosocial treatment whereas pharmacotherapy is a biological treatment. Modern cognitive neuroscience demonstrates that this distinction is a myth.

The past four decades have witnessed a transformation in research on the benefits of psychological therapies. However, even though therapists highlight that negative and adverse effects are seen in day-to-day practice, research on the negative effects of psychotherapy is insufficient. Given the unrelenting popularity of therapies, the argument for examining the adverse effects of psychotherapy would seem to be compelling. Such a strategy would extend beyond supervision of individual therapists to the introduction of monitoring systems that allow for a more systematic examination of failed psychotherapy interventions (such as exist for medication prescribing). The starting point could be the development of a consensus on how to define, classify and assess psychotherapy side-effects, unwanted events, adverse reactions, etc. This would provide a conceptual framework for communication, monitoring and research. This approach should not be viewed as an attack on therapies: every branch of medicine learns from mistakes, the same must surely be true for psychological treatments.