I am professor in genetic epidemiology.
1997 Associate professor (docent) in genetic epidemiology. Karolinska Institutet
2006 Professor in genetic epidemiology. Karolinska Institutet
2006-2013 Head of Swedish Twin Registry
2014-2017 Head of department
The work in my group is primarily concerned with using genetically informative samples (twins, families) to understand genetic and environmental influences on both health and behavior. The studies are usually based on the Swedish Twin Registry (located at the Department and comprising more than 140.000 twins) and other Swedish Registries such as the Multigenerational Register (comprising all individuals born in Sweden since 1931).
My group performs quantitative genetic studies - that is, evaluate the relative importance of genes and environments for a phenotype - and "cotwin-control"-studies, where the importance of an exposure is evaluated after controlling for genetic predisposition for the disease. The research is interdisciplinary and includes, among others, medical, genetic, epidemiological, sociological and psychological research questions.
One focus of the work in the group is to understand how genes and environments influence the development of health and behavior during childhood and adolescence. We have followed a cohort of 1.500 twin pairs longitudinally since they were 8 years old in 1994 with multiple contacts (1994, 1999, 2002, 2006, 2013) with both the parents and the twins themselves. We have studied how genetic and environmental effects contribute to the development of mental health problems over time. For example, we have found that genetic effects are more stable for ADHD (Chang, Lichtenstein et al. 2014) compared to internalizing problems (e.g., fears, anxiety) (Kendler, Gardner et al. 2008).
In CATSS-9, we conduct a psychiatric telephone interview with parents of all 1,400 twin pairs born in Sweden annually since 1992 in connection with their 9th birthdays. By April 2014 we have performed 13,500 interviews with a very high response rate (≈80%), and we have collected DNA from the twins. We follow the families with questionnaires to parents and twins at age 15 and 18. The aim is to understand how genes and environment affect different diseases and behavior during childhood and also to get information about various types of exposures. We have shown that the heritability for ASD was around 80% and that ASD had a common genetic etiology with other neuropsychiatric disorders (Lichtenstein, Carlstrom et al. 2010), that extreme values of ASD (Lundström, Chang et al. 2012) and ADHD (Larsson, Anckarsäter et al. 2012) have the same genetic etiology as normal variation in the underlying traits, and an association between fetal growth on ASD suggesting that fetal growth is in the causal pathway (Losh, Esserman et al. 2011).
To elucidate the mechanisms for the association between early risks and mental health problems as well as intergenerational transmissions of psychiatric problems, we use the large population based registries in Sweden, including, among others, information on all psychiatric care, criminal convictions and suicides in Sweden for all first-degree relatives (>15 million individuals) since 1932. Using different quasi-experimental methods we have shown that smoking during pregnancy is not causally related to offspring criminality (D'Onofrio, Singh et al., 2010), that there is a common genetic etiology between schizophrenia and bipolar disorder (Lichtenstein, Yip et al, 2009), and that ADHD medication protects against criminality (Lichtenstein, Halldner et al, 2012).
The Twin Registry
I was head of the Swedish Twin Registry during 2006-2013. During this time contacts with all twins not previously contacted in the Registry was completed. Now the Swedish Twin Registry contains of 200 000 twins. In addition, all twins in the Registry have had the opportunity to donate DNA for research purposes (n=40,000).
Current post docs
Current supervision of PhD students
- 1985 B. A. Department of Sociology, University of Stockholm
- 1993 Dr.Med.Sc. in genetic epidemiology. Institute of Environmental Medicine, Karolinska Institutet
- 1997 Associate professor (docent) in genetic epidemiology. Karolinska Institutet
Academic honours, awards and prizes
- 2011 James Shields Award For Lifetime Contributions To Twin Research
- 2013 Elected President for Behavior Genetics Association