Many young people outgrow their puberty problems, but others continue to struggle along. The TRacking Adolescents’ Individual Lives Survey (TRAILS) looks for the social, psychological and biological causes and the cohesion between them. Genetic factors are also investigated. For this purpose 2800 young people from the north of the Netherlands are being monitored from approximately age 10 until their 24th year of life. TRAILS not only looks at the individual but also looks at relations between children in the same grade, for instance. In TRAILS the UMCG and the University of Groningen collaborate with the universities of Rotterdam, Nijmegen and Utrecht and the Trimbos Institute.