"One of the striking things is that people have begun to lose hope of any quick break through and any chance that they might be going home," a staff member on the ground said.
Frances Guy, Christian Aid's Head of Middle East, told Premier workers returning from Lebanon noticed the diminishing hope in the camps.
He was speaking after Russia announced it is withdrawing its troops and equipment from Syria, after supporting President Bashar al-Assad's government forces with airstrikes.
Russian President Vladimir Putin has said his forces have "largely achieved their aim" in turning the tide of the war in Assad's favour and away from Islamic State and jihadists.
Some claim Russia has killed accidentally killed civilians and targeted moderate opposition groups, while others say Russia has only targeted Islamist groups and helped bring a long war, in which more than 250,000 have been killed and 6.6 million have been displaced, closer to an end.
Within the country 13.5 million remain in need of humanitarian assistance - including millions of children, the charity said.
The conflict is entering its sixth year now as peace talks resume in Geneva.
Syria's warring parties are involved in UN led peace talks two weeks into a cessation of hostilities brokered by the US and Russia.
The partial and temporary truce has seen reduced violence in Syria and more humanitarian aid getting into besieged areas.
Ms Guy said: "The cessation of hostilities may be fraying and peace talks look fragile, but we must build on this brief respite to offer Syrians hope that their country can be rebuilt and that violence can come to an end.
"We urge all parties to the conflict to help make the peace talks a success and bring an end to the conflict in Syria, help ensure continued humanitarian aid gets to those in need and give hope to the millions of people still suffering after 5 years of war. Shattered lives deserve to hope.
"As we reach the fifth anniversary of the beginning of the Syrian uprising it is easy to despair but despair is a betrayal of the positive and uplifting spirit of ordinary Syrians who continue to battle every day to help their fellow country men and women and who if given half a chance would return to rebuild their homes tomorrow."
