Genetic links to anxiety and depression are to be explored in the largest ever study into the issue, experts have announced.

Researchers are calling on people in England to sign up to the Genetic Links to Anxiety and Depression (Glad) study. It is hoped that 40,000 volunteers aged 16 and over will agree to be part of a database which will be used in future research studies to better understand the genetic aspects of mental health conditions.

The project, by the National Institute for Health Research BioResource and King’s College London, will see people with anxiety or depression enrol online and send a saliva sample by post.

“By recruiting 40,000 volunteers willing to be re-contacted for research, the Glad study will take us further than ever before,” said study lead Dr Gerome Breen, a geneticist at King’s College London.

“It will allow researchers to solve the big unanswered questions, address how genes and environment act together and help develop new treatment options.”

Research psychologist and study lead Prof Thalia Eley, of King’s College London, added: “We’re asking those who have experienced clinical anxiety or depression to complete a short survey and provide a DNA sample. We want to hear from all different backgrounds, cultures, ethnic groups and genders, and we are especially keen to hear from young adults. By including people from all parts of the population what we learn will be relevant for everyone.”

The news comes as the charity Rethink Mental Illness launched a campaign to encourage more young people – particularly those going to university – to spot the signs of psychosis. The charity said that psychosis affects one in 100 people and the first episode is most likely to happen aged 18-24.

Psychosis is a mental health problem that can cause people to suffer hallucinations or delusions. The charity said early signs can include withdrawing from friends, expressing unusual beliefs or saying they can see or hear things that are not real.

Brian Dow, deputy chief executive at Rethink Mental Illness, said: “It is important for everyone to know where to turn if they need help, but many students don’t think to sign up to their university’s GP.

“We would urge everyone to look out for your friends – if they are showing any of the early signs then encourage them to see their GP or go to A&E if you are worried about their immediate safety.”