In this article we assess and compare long-term adult socioeconomic status impacts from having experienced psychological and physical health problems in childhood. To do so, we use unique prospective data from the British National Child Development Study, a continuing panel study of a cohort of 17,634 children born in Great Britain during a single week in March 1958. To date there have been nine waves for this birth cohort to monitor their physical, educational, and social development, during childhood (at birth and 7, 11, and 16 y) and adulthood (age 23, 33, 42, 46, and 50 y). Excellent contemporaneous information exists throughout childhood on physical and psychological health, captured by doctor and nurse-led medical examinations and detailed parental and teacher questionnaires. This information is combined with a wealth of contemporaneous information on adult health and economic experiences collected from cohort members. Information includes their economic circumstances (earnings, labor supply, and other sources of family income), physical and psychological health, and relationship status. Large effects are found due to childhood psychological problems on the ability of affected children to work and earn as adults and on intergenerational and withingeneration social mobility. Adult family incomes are reduced by 28% by age 50 y, with sustained impacts on labor supply, marriage stability, and the conscientiousness and agreeableness components of the "Big Five" personality traits. Effects of psychological health disorders during childhood are far more important over a lifetime than physical health problems.U sing prospectively collected data beginning during the week of birth, repeated at three additional ages in childhood and adolescence, and extended into adulthood to age 50 y, this study investigates long-term adult impacts of having experienced psychological and physical health problems during childhood. Stimulated by the work of Barker (1), recent research has established evidence of a strong link between various aspects of poor physical health during childhood (and even in utero) and adult health (2-7) and economic outcomes later during adulthood (8, 9). Much less studied have been long-term health and socioeconomic (SES) consequences of psychological conditions experienced during childhood (10, 11). This is even more surprising given the substantial rise in psychological disorders affecting young people in the United Kingdom in the past 25 y (12, 13).Recently, Smith and Smith (14) used retrospective questions in the American Panel Study of Income Dynamics to find that impacts of childhood psychological problems on adult SES are large-a lifetime cost in lost family income of approximately $300,000 and total lifetime economic cost for all those affected of $2.1 trillion. An advantage of that study is that it compared siblings, so it was able to control for unobserved family and neighborhood effects, which were found not to be critical for this question. A disadvantage of that research is that it relied on...