PROJECT SUMMARY It is well established that parents play a critical role in setting the life trajectory of their children: predisposing their academic and social engagement, and ensuring an environment conducive to healthy development and goal fulfilment. Skills that will form the basis for social and socioeconomic success (e.g., attention, interpersonal ability), begin to shape early in life, with familial risk factors - such as low parental income, education, or health – negatively affecting such skill development. Children who face either more, or more long-term risk, factors are more likely to experience negative impacts extending from productivity (e.g., educational achievement), to socio- behavioural functioning (e.g., criminality), and the attendant challenges of each (e.g., reduced employment stability, impaired physical and mental health, lower life-expectancy) Prior research has suggested a particular relationship between parental mental illness and diminished outcomes across these domains in the next generation. However, the common practice of distinctly investigating maternal or (less commonly) paternal mental health – as opposed to unified investigation of the whole family unit - has limited insight into sex-differential effects and precluded investigation of risk dynamics by parent’s individual (or, where both parents are affected, combined) diagnoses. Further, the relative importance of parental mental health, as compared to alternative features with known impacts on child health and life opportunity (e.g., family socioeconomic status, offspring’s own mental health), remains largely unexplored. This fragmented approach has left, unquantified, the mechanistic role of parental mental health in cross-generational life outcomes – a point of public health concern given (1) the relationship of these outcomes (e.g., years of education, employment stability, criminality) to both the quality and duration of life, (2) the high proportion of Western children living with at least one mentally ill parent (11-18.2%), and (3) the rising rates of stress, mental illness, and related outcomes (e.g., suicide), among adults in these populations. The current project aims to assess the degree to which psychiatric disorders in parents impact key life outcomes (educational attainment, occupational stability, criminality) in the next generation, via analyses which allow these relationships to be enumerated and the underlying mechanisms parsed. Our aims – to 1) quantify the association of parental psychopathology (dual- vs. single-affected families; within vs. cross-disorder pairings) with offspring outcomes across the life-course; 2) assess the potentially differential effects of specific disorders on these associations; 3) examine the relationship of genetics and environment to these outcomes; and 4) disentangle the pathways through which familial environments interplay with offspring characteristics to impact the associations under study – have been d...