Editorial: Capturing the dynamics of development and psychopathology: from neural circuits to global trends.

Every year, the Journal of Child Psychology and Psychiatry dedicates an entire issue to state-of-theart reviews of the science underpinning our field, conducted by leading international experts. Like last year, the Editors sought to bring together a wide range of topics and thinkers covering many of the major themes that define contemporary child psychology and psychiatry. As always, the result is a veritable treasure trove of data and ideas on some of the most important topics of our times. For the second year running, we also invited commentaries from world-leading experts to accompany each review, and in every case the reviews and their commentaries create a fascinating, forward-looking dialogue about the hurdles that have been overcome, and the challenges that lie ahead. We are very grateful to all our authors and commentators for preparing such a rich feast for us. As you read the articles in the this year’s Annual Research Review issue, many common threads will no doubt strike you. To my mind, one notable feature of all the articles was the extent to which elegant research designs, and innovations in technology, have been, and will always be, the key to unlocking some of the central puzzles we are faced with when trying to elucidate the mechanisms of child psychopathology: the innovative use of MRI to reveal the complex structural and functional networks of neuronal organization (V ertes & Bulmore); the importance of well-chosen quasi-experiments to reveal the distinctive sequelae of adverse early care (Zeanah & Gleason), or throw light on the very earliest neurodevelopmental processes implicated in ASD and ADHD (Johnson, Gliga, Jones & Charman); the enormous value of consistent measurement and rigorous epidemiological sampling for charting, and understanding, variations in child psychopathology across nations (Polanczyk, Salum, Sugaya, Caye & Rohde), over the lifespan (Costello & Maughan), and over social periods (Collishaw); the use of rare genetic syndromes for disentangling the common and distinct developmental mechanisms involved in ADHD and other neurodevelopmental disorders (Scerif & Baker), and the major contribution of high-density genotyping, next-generation sequencing and large-scale international collaborative consortia for revealing the hidden heritability problem and pointing to some of the ways it can be tackled (Kiser, Rivero & Lesch). I was also struck by the fact all the authors showed a great willingness to embrace complexity. It is surely a mark of the growing maturity of our field that there is a greater acknowledgement and acceptance that there will be no simple answers to our questions: no single gene that directly causes disorder, no single experience with wholly predictable and lasting effects, no single phenotype to arise from familial risk, no single pathway or system affected by a rare genetic disorder; no one disorder has a common and inevitable long-term outcome. It must surely be no coincidence that this enthusiasm to take on the challenges of complexity are evident at a time when the field is energetically re-thinking the very nature and structure of psychopathology itself (National Institute of Mental Health, 2014). Each review also shows how, despite the complexity, good science can bring order out of the potential chaos. In doing so, all the reviews speak volumes for the importance of the developmental psychopathology framework for understanding child disorder and maladaptation. The ARR begins with an authoritative review of the nature, development andmanagement of attachment disorders by Zeanah and Gleason. The authors show just how much progress has been made in this highly complex area, by way of well-designed prospective and interventions studies, and the application of high-quality measurement tools. No doubt a further hidden ingredient in this productive process has been the capacity of those working in the field to ask some tough questions – most importantly: are previously labelled attachment disorders truly disorders of attachment? Here, Bowlby’s clear thinking about the function of attachment behaviour (Bowlby, 1969), and Ainsworth’s elegantly designed instrument for measuring it (Ainsworth, Blehar, Waters, & Wall, 1978), were extremely important for researchers to be able to home in on a relatively clear answer: children diagnosed with Disinhibited Social Engagement Disorder (DSED), as it is now known in DSM-5, may show apparently normal attachment behaviour. That DSED may not be, in a straightforward sense, a disorder of attachment is enormously important for how we think about the assessment and management of these difficulties. The fascinating discussion (in the accompanying commentary) between LyonsRuth and the authors also shows that there is much still to be resolved, particularly about the early causal developmental mechanisms at play and whether attachment plays some part in those. The developmental psychopathology perspective, and the good use of early-in-life prospective longitu-