This episode introduces the Dunedin Longitudinal Study, begun in 1972 and continuing today. It then looks at indicators in childhood behaviors identified by the study that can predict whether a person will have a more or a less stable and successful life as an adult. What are the basic indicators?

Troubled teens , why some go bad and others come right. What happens when young people run off the rails? Youth offending is very common, almost everyone does dumb things and many of us break the law. However youth offenders consist of two core groups; life present offenders (people who are going to continue offending regardless), and people who given the right conditions will return to become mainstream citizens.

The Dunedin Study has identified a fundamental developmental mechanism that completely rewrites the nature versus nurture argument. It is a genetic switch which is thrown by life events , nature loads the gun but nurture pulls the trigger. This chapter tracks the hunt for the mechanism using three specific examples - violence in men, depression, and cannabis induced schizophrenia.

The final instalment looks at the effects of modern life and aging , how excessive cleanliness affects asthma and allergies, how poverty gets under the skin to cause lifelong damage, the physical effects of social isolation, and predicting mental illness and Alzheimer's by just looking at the back of people's eyes. Plus the latest research and where the research is going next.