More than three-quarters of Syrian refugees may be suffering serious mental health symptoms, 10 years after the start of the civil war, The Guardian reports.

A UK charity is calling for more investment in mental health services for refugees in several countries after it found symptoms of post-traumatic stress disorder (PTSD) were widespread in a survey of displaced Syrians.

Syria Relief said refugees and people internally displaced by the conflict struggled to find support.

A survey of 721 Syrians living in Lebanon, Turkey and in Idlib in Syria’s north-west found 84% had at least seven out of 15 key symptoms of PTSD.

According to Syria Relief’s report, only 15% of refugees in Lebanon say mental health support is available for them. Among displaced Syrians in Idlib the figure falls to 1%.

Only two out of 393 people who took part in the survey showed no symptoms linked to PTSD in Idlib, the last rebel stronghold against President Bashar al-Assad’s forces.

More than 5.6 million people have fled Syria since 2011 and 6.6 million have been internally displaced.