"They talk about the earthquake. They build blocks and say... 'is this okay for earthquakes?' and 'is it stable?'," said teacher Busra Civelek, who was looking after 22 children in a makeshift classroom on a ferry that has been converted into a clinic and shelter in the port of Iskenderun.

They also play with toy fire engines. "They say... 'We have to go to the earthquake (zone) quickly'," she said.

The combined death toll in Turkey and Syria has climbed over 41,000, and millions are in need of humanitarian aid after being left homeless and without basic amenities.

Hasibe Ebru, a psychiatrist working on the ferry, said other people were crying a lot and had difficulty sleeping.

"I am telling (the quake survivors) that what they have been experiencing is normal and these symptoms will gradually decrease in a safe environment," she said.

"This really calms them down. They feel relieved when they learn that they are not going crazy, they are actually sane and that this is something any normal person would experience. We are monitoring them all day long."

The long-term mental health effects can only be understood with time as people process trauma in different ways, Ebru said.

The extent of the trauma survivors have experienced is enormous. Some have been pulled from the rubble after hours in the cold and darkness to discover family members have died or are missing, and the busy neighbourhoods where they lived have been reduced to mounds of shattered concrete.

Doctors have said they are treating increasing numbers of patients suffering from post-traumatic stress disorder and panic attacks after the quake.