One in every nine adults consistently had very poor or deteriorating mental health during the first six months of the Covid-19 pandemic, according to new research.

Those living in the most deprived neighbourhoods along with ethnic minority groups were severely affected, said the team based at The University of Manchester, King's College London, Cambridge, Swansea and City University.

The researchers also found that infection with Covid-19, local lockdown, and financial difficulties all predicted a subsequent deterioration in mental health.

However, two thirds of adults were in groups whose mental health was largely unaffected by the pandemic, finds the study published in The Lancet Psychiatry.

"We are increasingly aware that social and economic advantages have an important influence on how well people are able to cope with challenges that appear to have affected everyone equally," said Kathryn Abel, Professor from Manchester University.

"The health and social inequalities we already know about for women and for people in poverty relate to different burdens of stressful life events and different resources to deal with them.

"These remain relevant and are important reasons for the differences we are seeing in the mental health trajectories across the pandemic," Abel said.

The team analysed monthly surveys between April and October 2020 on 19,763 adults to identify typical patterns of change in mental health, revealing five distinct groups.

The unaffected groups were more likely to be older, white, and from the least deprived areas, with men being especially likely to have consistently very good mental health. Women and parents of school-aged children were particularly affected, but experienced significant improvements in mental health around the time schools' reopened.

Those who experienced a sustained decline or consistently very poor mental health were more likely to have had pre-existing mental or physical conditions. They were also more likely to be Asian, Black or mixed ethnicities, and live in the most deprived areas, according to the research.