One of Britain’s leading psychiatrists has warned that “all the dials are pointing the wrong way” on the nation’s mental health, as he raises concerns of post-traumatic stress disorder (PTSD) among patients and NHS staff in the aftermath of the pandemic.

Dr Adrian James, president of the Royal College of Psychiatrists, called for an urgent plan to deal with mental health issue, which he said could last for years after the immediate threat of the virus recedes.

In an interview with the Observer, he said that all Covid hospital patients should be screened for PTSD and offered follow-up help as a result of their ordeal, while he called for NHS staff to be monitored in case they were suffering as a result of their work during the pandemic.

“People should be screened for post-traumatic stress disorder before they leave, and then be followed up,” he said. “Most people who experience symptoms will spontaneously recover, but it’s actually still good to have a discussion back to your GP to check to make sure that things are recovering. A small but significant group of people will actually need psychological therapies in order to help them over that. And if they don’t get those, it can become really very, very chronic.”

He warned that between a third and a half of people who had been ventilated in hospital as a result of Covid experienced symptoms of PTSD, along with 20% of staff working in intensive care.

Experts warned last year that about half a million more people would experience a mental health difficulty as a result of the pandemic. It added that the pandemic was likely to increase the number of people in Britain experiencing a mental health problem for two years.

James said that a £500m government fund announced for mental health services needed to be allocated quickly and would have to be increased as the country attempted to get to grips with an increase in cases. “If you look at the social determinants of mental illness at the moment, all the dials are pointing the wrong way,” he said. “People haven’t been able to get the sort of support they’ve had before. We haven’t been meeting socially. Children haven’t been going to school. Some people are obviously in homes where they are really struggling.

“If you look at the last pandemic – at the beginning of the last century – we know that the mental health effects really spun out over a couple of years beyond it. In similar disasters, we know that the mental health effects tend to go on once the physical effects are under control. So it’s of great concern. Our services were already in a very challenging position. We know that we weren’t able to provide for everyone that needed mental health care before the pandemic. [The £500m funding] is a good start. But it really is a start, because we know and I think everybody accepts that this is going to roll on.”

He also warned that retaining exhausted staff would be another challenge. The shortage of trained staff could become a major restraint on the speed at which patients could be seen. “In the same way that the physical effects of Covid really mobilised government and health professionals, I think we’ve now got to have some really good hard planning around mental health,” he said.

James said there should be a national conversation about mental health that sees friends and family open up about how they are feeling as the country emerges from restrictions. “I think it’s actually going to be quite difficult for people to get back to the new normal,” he said. “One of the things we have noticed is that mental health is actually spoken about more often than it was, and Covid has started a conversation around that. We’re talking to friends and family more openly, perhaps in a way that we didn’t before.”

Nadine Dorries, the minister for mental health, said she was acutely aware of how difficult this pandemic has been and that the government remained committed to supporting wellbeing and mental health.

“We recognised this by keeping mental health services open throughout the pandemic and through the biggest increase in mental health funding in NHS history,” she said. “This funding will give more people the support they need, including for conditions like PTSD. We continue to strengthen our workforce, with 8,400 more people employed by the NHS mental health workforce in the past year alone.”