An International study which the Danish iPSYCH project has contributed to has now brought us one step closer to understanding why some people suffer from bipolar disorder.

2019.05.14 | Annette Bang Rasmussen

There are two types of bipolar disorder. Type 1 and type 2. The former is considered the classic form in which mania and – in many cases – also depression occur, while people with type 2 experience depressions and milder forms of mania.

After six years of work, researchers from Denmark and abroad have succeeded in uncovering genes which play an important role in the development of bipolar disorder, which was previously called manic depression.

“We’ve identified thirty places in our genome where genetic variations can affect the risk of developing bipolar disorder. This will help improve our understanding of the causes behind the development of the disease,” explains Professor Anders Børglum from Aarhus University and the national psychiatric project iPSYCH.

He has headed the Danish contribution to the study which has just been published in the scientific journal Nature Genetics.

In the study researchers have compared the genome of 29,000 people with bipolar disorder and 160,000 people who do not have the disorder. 

It is the largest genetic study of bipolar disorder and the researchers have identified completely new risk variants which often appear in the population and also point towards new biological mechanisms behind the disease. 

"The condition can be very serious and is characterised by pronounced changes of mood where both manic and depressive periods may occur. In addition to mood swings, people can also suffer from delusions, hallucinations and behavioural problems,” explains Anders Børglum.

New and better treatment in the long term

The disease usually begins with a period of depression and in Denmark between 50,000 - 100,000 people suffer from the disease during their lives, although many of them likely suffer less severe manic symptoms which they do not seek help for.

“We also found differences in the genetic composition between people with bipolar disorder type 1 and those with bipolar disorder type 2 where people don’t experience such severe episodes, but instead have several minor episodes of hypomania where they continuously feel slightly euphoric,” explains Anders Børglum.

In the analyses, the researchers also discovered that type 1 bipolar disorder shares a high degree of genetic risk factors with schizophrenia, while it appears that type 2 is more closely connected to depressive disorders.

"At the end of the day, we hope that our studies will lead to a better understanding of the molecular mechanisms that form the basis of bipolar disorder. This can provide a basis for developing new, more effective and better targeted treatments and will in this way hopefully significantly improve treatment and benefit the people suffering from this serious psychological condition and their relatives,” says Anders Børglum.

Background for the results

Type of study: Cohort study carried out in 14 countries in Europe, North America and Australia.

External funding: The Lundbeck Foundation and several international foundations including the Stanley Foundation and NIH/NIMH.

Partners: The study includes contributions from 207 institutions in 22 countries, primarily researchers from The Broad Institute at Harvard and MIT together with Massachusetts General Hospital in Boston, but also a number of international researchers and institutions who are organised in The Psychiatric Genomics Consortium.

The scientific article 'Genome-wide association study identifies 30 loci associated with bipolar disorder' has been published in the journal Nature Genetics.

Contact

Professor and Centre Director Anders Børglum
Aarhus University, Department of Biomedicine
Tel.: (+45) 6020 2720 
Email: anders@biomed.au.dk