The iPSYCH consortium has established a large Danish population-based Case-Cohort sample (iPSYCH2012) aimed at unravelling the genetic and environmental architecture of severe mental disorders. The iPSYCH2012 sample is nested within the entire Danish population born between 1981 and 2005, including 1.472.762 persons.

2017.11.20 | Annette Bang Rasmussen

Professor Carsten B Pedersen, NCRR, Aarhus University and Section leader Jonas Bybjerg-Grauholm, Section for Neonatal Genetics, Statens Serum Institut

About the study

This paper introduces the iPSYCH2012 sample and outlines key future research directions. Cases were identified as persons with schizophrenia (N=3540), autism (N=16 146), attention-deficit/hyperactivity disorder (N=18 726) and affective disorder (N=26 380), of which 1928 had bipolar affective disorder. Controls were randomly sampled individuals (N=30 000). Within the sample of 86 189 individuals, a total of 57 377 had at least one major mental disorder. DNA was extracted from the neonatal dried blood spot samples obtained from the Danish Neonatal Screening Biobank and genotyped using the Illumina PsychChip. Genotyping was successful for 90% of the sample. The assessments of exome sequencing, methylation profiling, metabolome profiling, vitamin-D, inflammatory and neurotrophic factors are in progress. For each individual, the iPSYCH2012 sample also includes longitudinal information on health, prescribed medicine, social and socioeconomic information, and analogous information among relatives. To the best of our knowledge, the iPSYCH2012 sample is the largest and most comprehensive data source for the combined study of genetic and environmental aetiologies of severe mental disorders.

The article “The iPSYCH2012 case-cohort sample: new directions for unravelling genetic and environmental architectures of severe mental disorders” was published in Molecular Psychiatry, 2017 Sept [Epub ahead of print].

Facts about the study

• Case-cohort study
• Representative sample of the Danish population (as opposed to samples of convenience)
• clinical diagnoses (as opposed to research diagnoses)
• First onset cases (as opposed to prevalent cases)

Further information

Carsten B Pedersen, National Centre for Register-based studies (NCRR), Aarhus University. Email:  cbp@econ.au.dk

Jonas Bybjerg-Grauholm, Section for Neonatal Genetics, Statens Serum Institut. Email: jorg@ssi.dk