TRAILS: Your life course in a database

If you are unlucky in life or your parents make a mess of things, does it change the course of your life? Will those who have developed psychiatric problems worsen over time, and do those who are lucky become stronger and stronger? UMCG researchers Tineke Oldehinkel and Karin Veldman want to learn more about the life course of young adults.

Tineke Oldehinkel is Professor of Life course Epidemiology of Common Mental Disorders at the Department of Psychiatry of the University Medical Center Groningen, and Karin Veldman is postdoc at the Faculty of Medical Sciences, specialised in the transition of young adults to the job market in the TRAILS cohort. To understand the life course of young people, with and without psychiatric problems, the UMCG decided to follow a large group of young people over a long period of time, and, to gather a very broad range of information about them. For this, the databiobank TRAILS was initiated: TRacking Adolescents’ Individual Lives Survey. 

TRAILS: The power of big data

TRAILS started to investigate a group of eleven-year-olds in the year 2000. The researchers also involved the environment of the children: parents, teachers and even classmates were interviewed. Next to information about mental health, researchers also collected information about biological factors, such as response to stress, and family circumstances. Every two years, researchers measure different factors in the lives of the participants. In the meantime, 22 years later, life-partners of the participants are included in the TRAIL cohort as well and researchers are observing how participants interact with their children. 

Mental health issues among young adults

Oldehinkel explains that psychiatric problems are very common in young people: at the age of 19, almost half of the 2500 participants has already met the criteria of a psychiatric disorder. Moreover, health problems have the tendency to cluster: participants often simultaneously have multiple health issues. For example, social health problems and unhealthy behavior, such as smoking or excessive use of alcohol, often accompany psychiatric disorders. This enhances the chance of more problems in the future.

Story of hope

According to Oldehinkel, TRAILS data brings us both a reason for concern as well as a reassuring message. 0ldehinkel: ‘’Things can change in all directions, psychiatric problems in youth do not always remain in adulthood. And even then if they do, having psychiatric complaints does not always imply that someone is unhappy. On the contrary: about 90% of our participants indicate that they generally feel quite, or even very happy. Therefore, there is a reason for concern, but also for optimism.” 

Participation on the job market

Contrary to expectations, the group of young people dropping out of the job market due to psychological problems is not very big. Veldman: ‘’Most adolescents who had psychiatric complaints as a teenager, are able to successfully find a job. TRAILS data shows quite well that there is a group of people with psychological problems that do find paid jobs, have a social life, find a partner and have children. There is only a small group of people with psychological problems that drops out.’’ 

Growing with the TRAILS cohort 

TRAILS continuously adapts the questions and methods to the current age of the participants.  Sometimes that resulted in new insights and possibilities. Oldehinkel explains how TRAILS’ first focus was the transition from primary school to secondary school and puberty. Later, they focused on romantic relations and first sexual experiences and now they focus on the balance between work and private life, and parenthood.


Participants also profit from joining the TRAILS research cohort. Veldman: ‘’We communicate the results of the study on our website, and, we developed an online course for teenagers. Here, they can find reliable information about psychological complaints, and learn how to deal with them. The course is available both in Dutch and English, and is quite popular, so the course really serves the need of the teenagers.’’

The added value of longitudinal cohorts

A biodatabank that includes longitudinal data over a long period of time, is of added scientific value. Oldehinkel explains: “Individual studies that include a specifically selected group of participants, often show spectacular results, but these results can often not be translated to the general public. In addition, not all short-term effects have long-term consequences. And, if two factors cohere, it is simply never true that one factor completely causes the other.’’

Influence of individual factors relatively small

Because so many factors influence our life course, the influence of each individual factor is rather small. This is one of the most important outcomes that researchers found with TRAILS data. While in many studies only one factor at a time is investigated, for example the influence of divorcing parents, TRAILS data combines multiple factors and also reveals the importance of the influence of the understanding teacher. 

Continuous development

Oldehinkel: ‘’When we started with TRAILS, the possibilities regarding genetic information were limited and very expensive. This changed quickly, and at first we could collect the code for a few genes to link them to behavioral aspects. A few years later, we could sequence the complete genome for participants. With this technology, it became more and more clear to us that a person’s characteristics or vulnerabilities cannot be simply linked to one or two genes. It usually is a (large) combination of genes that form a risk or protective factor in development.‘’ 


Veldman continues: “On the other hand, the stability of TRAILS is interesting. We decided not to change anything after the start of the corona pandemic. We had just finished a measurement before it started, so in our next measurement we able to investigate the consequences of having developed long-COVID.’’     

More information about TRAILS.

The online course about mental health.