It is again my pleasure to work with an outstanding group of contributors in the production of this, the 10th Annual Research Review. As always our goal is to solicit reviews from authorities in the field, which will serve to update the readership on aspects of current research and emerging research trends. Authors are encouraged to be selective, rather than comprehensive, in coverage and to focus on the aspects of research they feel are most important. In addition to thanking the authors, I am also grateful to the various referees who provided thoughtful and detailed commentary to the authors, which has enriched the papers further. As noted in last year's editorial, we are now beginning to return to topics covered in previous reviews.

It is a particular pleasure to have Professor Rutter and colleagues provide an update of his earlier (1990) review of genetics and child psychiatry. The first of their two papers provides a summary of advances in quantitative psychiatric genetics with particular attention to both conceptual and methodological advances. Important shifts in research strategies are noted. In the second paper Rutter and colleagues focus more specifically on advances relative to specific disorders. It is clear that work in this area is likely to advance our knowledge substantially in the years ahead in ways that we can now only begin to appreciate. Angold, Costello, and Erkanli have provided a very helpful review of the topic of comorbidity in the psychiatric disorders of childhood adolescence. This is an area of some controversy and their review provides a valuable summary of current knowledge. Stevenson addresses issues in the treatment of the long-term sequelae of child abuse; he notes that while considerable progress has been made, important questions regarding treatment and prevention remain to be answered. Filipek reviews the current state of knowledge on neuroimaging in the developmental disorders. Advances in the field have given us the opportunity to understand fundamental aspects of brain-behavior relationships. Finally, Hetherington and Stanley-Hagan review current knowledge regarding the effects of divorce on children; this topic is an increasingly important one in terms of both research and intervention.

For the 11th edition of the Annual Research Review we anticipate that topics covered will include language acquisition, substance abuse, intersubjectivity, child abuse, effects of HIV infection on children, and advances in psychological assessment methods.

Advances in quantitative psychiatric genetics as a whole are reviewed with respect to conceptual and methodological issues in relation to statistical model fitting, new genetic designs, twin and adoptee studies, definition of the phenotype, pervasiveness of genetic influences, pervasiveness of environmental influences, shared and nonshared environmental effects, and nature–nurture interplay. Advances in molecular genetics are discussed in relation to the shifts in research strategies to investigate multifactorial disorders (affected relative linkage designs, association strategies, and quantitative trait loci studies); new techniques and identified genetic mechanisms (expansion of trinucleotide repeats, genomic imprinting, mitochondrial DNA, fluorescent in-situ hybridisation, behavioural phenotypes, and animal models); and the successful localisation of genes.

Key substantive findings from quantitative and molecular genetic research are reviewed in relation to affective disorder, schizophrenia, autism, hyperkinetic/attention deficit disorder, oppositional and conduct disorders, drug/alcohol problems, and Tourette's syndrome/chronic tics.

We review recent research on the prevalence, causes, and effects of diagnostic comorbidity among the most common groups of child and adolescent psychiatric disorders; anxiety disorders, depressive disorders, attention deficit hyperactivity disorders, oppositional defiant and conduct disorders, and substance abuse. A meta-analysis of representative general population studies provides estimates of the strength of associations between pairs of disorders with narrower confidence intervals than have previously been available. Current evidence convincingly eliminates methodological factors as a major cause of comorbidity. We review the implications of comorbidity for understanding the development of psychopathology and for nosology.

The literature on the long-term sequelae of sexual and physical abuse is reviewed. Abused children are at risk of long-term adverse psychological sequelae related to the abuse per se and not just as a consequence of other associated background factors. There is some specificity relating the type of psychological outcome to the type of abuse experienced. Physical abuse is just as traumagenic as sexual abuse in the long-term. Whatever the efficacy of specific psychological treatments, there are broad general service measures that will prevent both abuse and re-abuse and therefore impact on long-term sequelae. The studies on the effectiveness of intervention to prevent psychological sequelae of abuse are systematically appraised. There are few well-conducted and adequately controlled studies of the efficacy of treatment for abused children. Where a corpus of studies does exist, e.g. group therapy for sexually abused children, treatment for abused children appears to be as effective for children whose problems arise from other causes. Studies have also shown that abusive parenting can be changed by training.

The developmental disorders of childhood — autistic, developmental language, reading (dyslexia), and attention deficit-hyperactivity disorders — manifest with deficits in the traditional behavioral domains of cognition, language, visual-spatial function, attention, and socialization. However, none of these disorders has been associated with characteristic discrete focal lesions or recognized encephaloclastic processes. Developmental cognitive neuroscientists must therefore begin with the spectrum of sometimes divergent behaviors occurring within these disorders and work backward in an attempt to identify the responsible anomalous neural systems. Since the advent of “brain imaging” two decades ago, much effort has focused on identifying brain-behavior correlates in these disorders. The results of these neuropathologic, structural, and functional neuroimaging studies are presented and the reasons for the often divergent findings are discussed. As we approach the end of the Decade of the Brain, current neuroimaging techniques give us the technology for the first time to apply a fundamental cognitive approach to brain-behavior relationships in the developmental disorders, to eliminate the conglomeration of “apples and camels” phenomenon. Researchers are working together to create comparable protocols and to adhere to methods that can be replicated across sites. The future prospects for a greater understanding of the developmental disorders are now much brighter with neuroimaging technology.

This review addresses major questions about divorce, around which much contemporary research is oriented. These involve questions of the consequences of divorce for the adjustment of children and the vulnerability and resiliency of children in coping with divorce, whether children are better off in a conflictual intact family situation or a divorced family, and how mothers, fathers, and clinical or educational interventions can moderate the effects of divorce. Although research in the past decade has yielded considerable information about these questions, issues that need further investigation are also presented.