Here are five papers on childhood, the effects childhood experience can have on adulthood, and the effects adults may then have on their own children.  The first paper by Brody et al. is the encouraging one.  It demonstrates how caring parenting can combat genetic vulnerability - "involved-supportive" mothering greatly reduced the link between vulnerable genes and subsequent youth substance abuse.  The Van Meurs et al study shows the reverse - how problem behaviours in one generation of children increases the likelihood that, when these children become parents themselves, their own children will develop similar problem behaviours.

The final three studies all demonstrate ways in which childhood difficulties spill over into adult problems.  So Dube and colleagues studied data on Adverse Childhood Experiences (see related ACE questionnaire & link) and concluded "Childhood traumatic stress increased the likelihood of hospitalization with a diagnosed autoimmune disease decades into adulthood. These findings are consistent with recent biological studies on the impact of early life stress on subsequent inflammatory responses."  Goodwin et al. found that "Significant linkages emerged between childhood mental health problems (in boys) and obesity, atopic eczema, epilepsy and asthma in early adulthood."  While Lee and colleagues found that number of childhood adversities and early onset childhood anxiety or depression both independently increased the chances of developing headache problems in adulthood.

Therapeutically this leaves me with a couple of thoughts.  One is the potential value of interventions to improve parenting in vulnerable families (for example, see a study on the Incredible Years positive parenting programme).  The other is the benefit often obtainable from psychological interventions for some adult "physical" disorders.  There are obvious recent examples for major diseases such as cancer and cardiac problems, as well as recent studies on trauma processing, improved wound healing and benefits for immune function.

Brody, G. H., S. R. Beach, et al. (2009). "Parenting moderates a genetic vulnerability factor in longitudinal increases in youths' substance use." J Consult Clin Psychol 77(1): 1-11. [PubMed] 
The authors used a longitudinal, prospective design to investigate a moderation effect in the association between a genetic vulnerability factor, a variable nucleotide repeat polymorphism in the promoter region of 5HTT (5-HTTLPR), and increases in youths' substance use. The primary study hypothesis predicted that involved-supportive parenting would attenuate the link between the 5-HTTLPR polymorphism and longitudinal increases in substance use. African American youths residing in rural Georgia (N = 253, mean age = 11.5 years) provided 4 waves of data on their own substance use; the mothers of the youths provided data on their own parenting practices. Genetic data were obtained from youths via saliva samples. Latent growth curve modeling indicated that 5-HTTLPR status (presence of 1 or 2 copies of the s allele) was linked with increases in substance use over time; however, this association was greatly reduced when youths received high levels of involved-supportive parenting. This study demonstrates that parenting processes have the potential to ameliorate genetic risk.

Van Meurs, I., J. Reef, et al. (2009). "Intergenerational Transmission of Child Problem Behaviors: A Longitudinal, Population-Based Study." Journal of Amer Academy of Child & Adolescent Psychiatry 48(2): 138-145. [Abstract/Full Text] 
Objective: From a developmental perspective, it is important to know to what extent childhood problem behaviors are transmitted across generations. In a longitudinal community study, we compared child behavior of parents with the behavior of their offspring. Intergenerational transmission was investigated for a broad range of problem behaviors, including internalizing problems and externalizing behavior. Sex differences were investigated as well. Method: We compared Child Behavior Checklist scores of 4- to 16-year-old children (N = 271) from a community sample assessed in 1983 with Child Behavior Checklist scores of their 6- to 18-year-old offspring (N = 424) who were assessed in 2007. Multilevel modeling was used to test intergenerational associations. Results: Most forms of problem behavior in children were predicted by the behavior of their parents as children. Parents' Internalizing, Externalizing, and Total Problem scores in childhood all predicted similar problems in their children. Sex differences were found for Delinquent Behavior: continuity was stronger in mothers than it was in fathers, and it was also stronger in sons than in daughters. Conclusions: The finding that child behavior continues across generations poses challenges in finding ways to prevent problems from being transmitted across generations.

Dube, S. R., D. Fairweather, et al. (2009). "Cumulative Childhood Stress and Autoimmune Diseases in Adults." Psychosom Med 71(2): 243-250.   [Abstract/Full Text] 
Objective: To examine whether childhood traumatic stress increased the risk of developing autoimmune diseases as an adult. Methods: Retrospective cohort study of 15,357 adult health maintenance organization members enrolled in the Adverse Childhood Experiences (ACEs) Study from 1995 to 1997 in San Diego, California, and eligible for follow-up through 2005. ACEs included childhood physical, emotional, or sexual abuse; witnessing domestic violence; growing up with household substance abuse, mental illness, parental divorce, and/or an incarcerated household member. The total number of ACEs (ACE Score range = 0-8) was used as a measure of cumulative childhood stress. The outcome was hospitalizations for any of 21 selected autoimmune diseases and 4 immunopathology groupings: T- helper 1 (Th1) (e.g., idiopathic myocarditis); T-helper 2 (Th2) (e.g., myasthenia gravis); Th2 rheumatic (e.g., rheumatoid arthritis); and mixed Th1/Th2 (e.g., autoimmune hemolytic anemia). Results: Sixty-four percent reported at least one ACE. The event rate (per 10,000 person-years) for a first hospitalization with any autoimmune disease was 31.4 in women and 34.4 in men. First hospitalizations for any autoimmune disease increased with increasing number of ACEs (p < .05). Compared with persons with no ACEs, persons with >1 ACEs were at a 70% increased risk for hospitalizations with Th1, 80% increased risk for Th2, and 100% increased risk for rheumatic diseases (p < .05). Conclusions: Childhood traumatic stress increased the likelihood of hospitalization with a diagnosed autoimmune disease decades into adulthood. These findings are consistent with recent biological studies on the impact of early life stress on subsequent inflammatory responses.

Goodwin, R. D., A. Sourander, et al. (2009). "Do mental health problems in childhood predict chronic physical conditions among males in early adulthood? Evidence from a community-based prospective study." Psychological Medicine 39(02): 301-311. [Abstract/Full Text] 
Background Previous studies have documented associations between mental and physical health problems in cross-sectional studies, yet little is known about these relationships over time or the specificity of these associations. The aim of the current study was to examine the relationship between mental health problems in childhood at age 8 years and physical disorders in adulthood at ages 18-23 years.  Method Multiple logistic regression analyses were used to examine the relationship between childhood mental health problems, reported by child, parent and teacher, and physical disorders diagnosed by a physician in early adulthood.  Results Significant linkages emerged between childhood mental health problems and obesity, atopic eczema, epilepsy and asthma in early adulthood. Specifically, conduct problems in childhood were associated with a significantly increased likelihood of obesity and atopic eczema; emotional problems were associated with an increased likelihood of epilepsy and asthma; and depression symptoms at age 8 were associated with an increased risk of asthma in early adulthood.  Conclusions Our findings provide the first evidence of an association between mental health problems during childhood and increased risk of specific physical health problems, mainly asthma and obesity, during early adulthood, in a representative sample of males over time. These data suggest that behavioral and emotional problems in childhood may signal vulnerability to chronic physical health problems during early adulthood.

Lee, S., A. Tsang, et al. (2009). "Association of headache with childhood adversity and mental disorder: cross-national study." The British Journal of Psychiatry 194(2): 111-116. [Abstract/Full Text] 
Background Community studies about the association of headache with both childhood family adversities and depression/anxiety disorders are limited. Aims To assess the independent and joint associations of childhood family adversities and early-onset depression and anxiety disorders with risks of adult-onset headache. Method Data were pooled from cross-sectional community surveys conducted in ten Latin and North American, European and Asian countries (n=18 303) by using standardised instruments. Headache and a range of childhood family adversities were assessed by self-report. Results The number of childhood family adversities was associated with adult-onset headache after adjusting for gender, age, country and early-onset depression/anxiety disorder status (for one adversity, hazard ratio (HR)=1.22-1.6; for two adversities, HR=1.19-1.67; for three or more adversities, HR=1.37-1.95). Early and current onset of depression/anxiety disorders were independently associated (HR=1.42-1.89) with adult-onset headache after controlling for number of childhood family adversities. Conclusions The findings call for a broad developmental perspective concerning risk factors for development of headache.