Background The psychological sequelae of obesity have been well studied.

There is emerging evidence that childhood psychological function may have implications for subsequent adult obesity. Maternal psychological function has also been implicated. Identification of psychological factors in childhood related to subsequent overweight may contribute to preventing obesity across the life course.

Design The authors undertook life-course analyses using the 1970 British birth cohort.

Outcomes Obesity at 26, 30 and 34 years.

Predictors Maternal- and teacher-reported child psychological function (general behavioural, conduct, emotional or attentional/hyperactivity problems) and maternal psychological function.

Analyses Logistic regression models for risk of adult obesity were adjusted for socioeconomic status, parental body mass index (BMI), birth weight, childhood BMI, cognitive ability and adult social class.

Results Complete data on childhood psychological function and adult obesity were available on 6768 subjects. Generalised behavioural problems at age 5 years increased the risk of obesity at 30 years (adjusted OR (AOR)=1.5 (95% CI 1.2 to 1.8) p=0.001) and at 34 years (AOR=1.3 (1.0 to 1.6) p=0.03). Persistence of these problems through childhood (ie, also present at 10 years) further increased obesity risk at 30 years (AOR 1.9 (1.3 to 2.7) p=0.001). Chronic conduct problems at 5 and 10 years also increased obesity risk at 30 years (AOR 1.6 (1.1 to 2.4) p=0.01). Inattention/hyperactivity at 10 years similarly increased risk of obesity at 30 years (AOR 1.3 (1.0 to 1.6) p=0.04). Childhood emotional disorders and maternal psychological function were not associated with adult obesity.

Conclusion Chronic childhood behavioural problems increase the risk of adult obesity by up to 90% after adjustment for childhood BMI. Risk increases most with early and persistent problems. Adult obesity risk was predominantly related to childhood conduct and attentional/hyperactivity problems. Strategies to prevent or reduce obesity should include a focus on psychological function in childhood, particularly conduct and attentional problems.