The largest-ever genetic study of schizophrenia has identified large numbers of specific genes linked to the disorder.

Researchers found a greater number of genetic links to schizophrenia than ever before, in 287 different regions of the genome – the human body’s DNA blueprint.

Within these regions, they were able to identify 120 genes likely to contribute to the disorder.

Experts say the findings are a step towards understanding the causes of the condition and identifying new treatments.

Schizophrenia is a serious psychiatric disorder that causes a range of different psychological symptoms including hallucinations and delusions.

It starts in late adolescence or early adulthood, and, according to the World Health Organisation, affects about one in 300 people worldwide.

Co-lead author Professor Michael O’Donovan, from the division of psychological medicine and clinical neurosciences at Cardiff University, said: “Previous research has shown associations between schizophrenia and many anonymous DNA sequences, but rarely has it been possible to link the findings to specific genes.

“The present study not only vastly increased the number of those associations, but we have now been able to link many of them to specific genes, a necessary step in what remains a difficult journey towards understanding the causes of this disorder and identifying new treatments.”

Hundreds of researchers across 45 countries analysed DNA from 76,755 people with schizophrenia and 243,649 without it.

As well as identifying the specific genes, the Psychiatric Genomics Consortium study found the genetic risk for schizophrenia is seen in genes concentrated in brain cells called neurons, but not in any other tissue or cell type.

Professor James Walters, co-lead author on the Cardiff-led paper and director of the MRC Centre for Neuropsychiatric Genetics and Genomics at Cardiff University, said: “Whilst people with schizophrenia can recover, many do not respond well to treatments, experience long-term problems with their mental and physical health, as well as impacts on relationships, education and work.

“We hope the findings in this, and the companion studies, can be used to advance our understanding of the disorder and facilitate the development of radically new treatments.

“However, those processes are often not straightforward and a lot of work by other neuroscientists is needed to translate the genetic findings into a detailed understanding of disease mechanisms.”

The findings are published in the Nature journal.

In a linked paper, landmark research involving scientists at UCL identified for the first time 10 genes with extremely rare mutations that significantly increase an individual’s risk of developing schizophrenia.

According to the SCHEMA Consortium paper published in Nature Genetics, in one instance this was by more than 30-fold.

Professor Andrew McQuillin, co-author of the papers and head of the UCL Molecular Psychiatry Laboratory (UCL Division of Psychiatry), said: “We have now been able to detect specific genes, a necessary step in the challenging journey towards understanding the causes and mechanisms of any disorder.”