Mental health reflects an array of causal influences that span biological, psychological, and social circumstances, with resultant underlying causal pathways to poor mental health outcomes in childhood that are complex. Key features of this complexity are reciprocal interactions between person and environment that take place over time. The core of this thesis seeks to attend to the complexity of development to move the field of developmental health forward toward greater explanation, and more successful prediction and prevention. The focal point of the thesis is the psychosocial determinants of childhood mental health, the resource domain of the developing child, and the interplay between characteristics of the individual child, the family, and the community. The eventual goal is to better understand why and how socioeconomic circumstances impact on developmental health. One component of this thesis focuses on the expansion of extant developmental theory. The other component focuses on the development of an analytic strategy that more appropriately reflects the intricacies of this theoretical expansion. In the process, data are analysed, principally as a heuristic strategy, to illustrate the analytical approach needed to support the theoretical framework. The specification of a bioecological conceptual framework suitable to guide research and policy in developmental health is the first principal objective of the thesis. A critical examination of the resource framework proposed by Brooks-Gunn, Brown, Duncan, and Anderson Moore (1995) reveals it to be centred on family and community resources, but otherwise silent with respect to the physical and psychological resources of the child. The quintessential point of this thesis is that theory in developmental health must be able to account for the contribution individuals make to their own development. A modified resource framework is proposed that acknowledges financial, physical, human, and social capital, within the domains of the individual child, the family, and the community. The second principal objective of the thesis, the development of analytical methods that focus on the individual child and the complexity of data generated by this theoretical approach, is then introduced. Theory and method are thus integrated when comprehensive measures of characteristics in multiple domains across developmental periods are modeled using longitudinal data from the Western Australian Pregnancy Cohort (Raine) Study (Newnham, Evans, Michael, Stanley, & Landau, 1993). The mothers of 2,860 children were enrolled at 18 weeks in pregnancy and the children have been followed at birth, one, two, three, five, and eight years of age. Eighty-nine per cent (2,537 /2,860) of families were available for follow-up at eight and 74 per cent (2,126/2,860) of families responded. Extensive demographic, psychological, and developmental data were available for the children and their families and a limited amount of data were available for the communities in which they reside. A measure of mental health morbidity, the Child Behaviour Checklist (Achenbach, 1991), was available for the children at two, five, and eight years of age. In the first instance, dichotomous summary variables are derived for the demographic, psychological, and developmental variables of interest. Variables are then selected for inclusion in one of several explanatory models. To create a mathematical representation of resource characteristics, the information for each child is concatenated as a series of binary strings. Frequency tabulation is then used to aggregate the data and odds ratios are calculated to determine the degree of risk associated with each string of code, or pattern of factors relative to a nominated mental health outcome. The results provided a scaffold from which this theoretical and analytical approach is compared and contrasted with the reviewed literature. Two principal themes of investigation are pursued. The first theme to be examined is the interplay between characteristics of the child, family, and community and the contribution children make to their own development. The specific approach models the interaction between selected characteristics of the child, family and community in each of four developmentally significant time periods. The theoretical position adopted in the present study suggests that the effect of any personal or contextual factor on later development, if a relationship does truly exist, is most likely to be differential. That is, it is a combination of influences that determines developmental outcomes for children, not any single factor acting independently. The modelling process demonstrates that, for the children involved, personal and contextual factors impact mental health differentially depending on various other individual, family and/or community characteristics. The modelling process identifies patterns of factors that impact relatively small, but significant, numbers of children because the models focus on the effect for individual children rather than the effect for the group. For example, one model suggests that the effect of intra-uterine growth restriction for the group as a whole may be minimal, but the impact for some children could be critical depending on the combination of family and community influences, such as the mothers level of education, the family’s experience of significant life stress, and residence in a relatively disadvantaged community. The second theme to be examined is the possibility that the accumulation of resource deficits or risk characteristics, over time, amplifies the likelihood of mental health problems in childhood. The approach models selected characteristics of the child in each of the four periods of development collectively, and it also models selected characteristics spanning each of the four time periods discretely. The results suggest that latency, pathway, and recency effects may operate simultaneously, and that timing and accumulated burden may both be important determinants of risk. For example, with regard to children whose family experienced life stress, these three effects operated in a systematic way to increase the degree of risk of a mental health problem. In summary, the aggregation of data at the individual level is a productive approach in seeking to explain population level social phenomena. While seemingly paradoxical, the identification of the joint, interactive effects between individual, family, and community characteristics, better allows for the quantification of family and community characteristics operating through multiple causal pathways.