A major study into depression involving the data of more than two million people has identified personality types susceptible to the condition.
Scientists led by the University of Edinburgh analysed health and DNA records, after which they pinpointed 269 genes linked to depression.
Using a research method known as Mendelian randomisation, they identified sections of DNA common in people with depression and in those who adopted “lifestyle behaviours” such as smoking.
The findings suggest depression could be a driving factor leading some people to smoke, researchers said.
They also found neuroticism – a tendency to be worried or fearful – could lead people to become depressed.
The team is inviting people with depression or anxiety to take part in a further study to help understand more about the role of DNA in common mental health conditions.
The research, known as the Genetic Links to Anxiety and Depression (GLAD) Study, aims to improve the lives of people with mental health issues.
Working with the National Institute of Health Research Mental Health BioResource and King’s College London, they hope to collect saliva samples and questionnaires from 40,000 people across the UK.
Professor Andrew McIntosh from Edinburgh University’s Centre for Clinical Brain Sciences said: “These findings are further evidence that depression is partly down to our genetics.
“We hope that by launching the GLAD study we will be able to find out more about why some people are more at risk than others of mental health conditions and how we might help people living with depression and anxiety more effectively in future.”
The research, published in Nature Neuroscience, was funded by Wellcome and the Medical Research Council.
Raliza Stoyanova, of Wellcome, said: “Given that current treatments work for only half of those who need them, the study provides some intriguing clues for future research to follow up – for example that biological pathways involved in developing the condition may not be the same as those involved in responding to treatment.”
Mental health research charity MQ said there had been little advancement for people living with depression in almost 50 years.
Director of research Sophie Dix said: “This study adds to the weight of evidence that genes are one of the key risk factors in depression, which is also impacted by life events such as social environment and trauma.
“The value of this could really be seen when looking into the development of personalised treatments – a welcome step given the dearth of innovation in identifying new approaches.
“The power of this big genetic study is that it can point to systems in the brain which adds to our currently limited understanding in this area.
“By increasing our understanding of these systems and how the social environment affects biological risk factors, we can begin to identify new targets for treatments that could help the millions of people worldwide affected by depression.”
