As you might guess from the title of my editorial, this issue contains a real mixture of papers covering approaches ranging from prevention and clinical trials to examination of associates of partner violence in teenagers, via clinical characterisations, basic experimental science and longitudinal studies. I am sure there will be something of interest for all. We begin with a scholarly and authoritative review by Spence and Shortt of prevention trials for depression among children and adolescents. This is without doubt essential reading for anyone interested in prevention trials in any area, and provides a thorough overview of the issues involved in their approach as a whole and with regard to those studies of depression in particular. The take-home message so far appears to be that we shouldn't rush out and fund wide-scale prevention trials, but that there is hope that these may be effective if we can only get some more really good-quality studies of this kind undertaken. Ideas for how to conduct a really excellent prevention programme are also discussed. The second paper by Melhuish and colleagues explores reasons for the varied levels of success of the ‘Sure Start’ programme, aimed at improving outcomes in a rather general way for those children from disadvantaged neighbourhoods. They find evidence for some association between aspects of implementation and success of intervention, which provides useful pointers for future work in this costly and difficult area. As noted by Spence and Shortt, the prevention literature generally lags behind that of clinical trials, and an area where these have proven very successful is in the eating disorders literature. The next paper (Eisler et al.) is a rare 5-year follow-up of one such trial, and reveals that family therapy is highly effective, while also indicating that as noted in earlier stages of the study, the use of conjoint family meetings is less helpful than other approaches for families with high parental criticism. The following two papers examine somewhat specific clinical features of distinct disorder groups. The first is a fascinating study (Kirov et al.) showing that the sleep problems known to plague children and adolescents with ADHD and with tic disorders are very different, and that those unfortunate sufferers with both conditions present with both types of sleep problem. Such difficulties are likely to have very high impact on these patients. The next paper examines smiling as a means of attracting adult attention in children with Angelman syndrome (Oliver et al.). This syndrome results from the loss of a section of DNA but only where the chromosome originated from the father (if it originated from the mother the effect on the child is Prader-Willi syndrome). The authors interpret their data in the light of the theory that imprinting (differential effects where they are of paternal versus maternal origin) has an evolutionary role. Thus the increased smiling seen in these children, and their superior ability to gain adult attention by smiling, is interpreted as being an evolutionary tactic to gain maternal (or other adult) attention. Interactions between risk factors for depression underlie the next two papers. In the first, by Shirtcliff et al., a steroid (DHEA) was examined in conjunction with stress. In girls, levels of DHEA not only rose during a public speaking task, but also failed to normalise in the afternoon following the task, suggesting that this may be a marker for stress reactivity. In a rather different study, Medina et al. found that in addition to main effects of each there was an interaction between marijuana use and brain white-matter volume on depressive symptoms in adolescents. Two different clinical groups are considered in the next two studies, both of which take a longitudinal approach. Van Lier et al. use oppositional defiant disorder and attention deficit disorder trajectories as predictors of conduct disorder. They find that both are relevant in girls, but only oppositional behaviour in boys, suggesting that gender differences are key to understanding the onset of conduct disorder. Snowling et al. examined reading- and writing-related skills in children at risk from dyslexia owing to their family history. They found evidence in early adolescence for ongoing serious problems with reading and writing and conclude that an emphasis needs to be placed on making sure these children are encouraged and helped with these activities so as not to compound their genetic risk with lack of adequate learning and support. Finally, the paper by Flisher et al. reported that over 20% of adolescents from a developing country (S. Africa) who were in a relationship reported having been physically violent towards their partner. Partner violence was associated with attitudes towards violence, general social influences and outcome expectancy, and intentions to be violent. This offers potential routes for the type of preventative programmes that the issue begins with.