Some of those attending the winter solstice celebrations at Stonehenge were there to worship, others to party or to simply to enjoy the rise of the sun after the longest night and look forward to lengthening days and springtime.

Despite it being a gloomy, soggy morning in Wiltshire, there was a joyful atmosphere as hundreds of people gathered to witness the light return.

There is evidence that spending time near or within the standing stones can actually be good for mental wellbeing.

One of the most intriguing schemes that has taken place at Stonehenge this year is the Human Henge project run by bodies including the mental health charity the Restoration Trust.

Groups of people with mental health problems have been guided around the ancient landscape by experts and have taken part in activities that have been going on at the site for centuries, ranging from baking bread to making clay pots. The culmination of the activities is a chance to spend time within the great stone circle.

At a conference in Cardiff this week, the project revealed that by the end of the sessions participants reported that they felt closer to others and better able to deal with problems. Four per cent of them felt optimistic at the start but by the end this had risen to 17%.

Laura Drysdale, the director of the Restoration Trust, said she believed the success was connected to the ancientness of the landscape and the power of the stone circle itself.

The scene at Stonehenge this morning. Photograph: Matt Cardy/Getty Images

“It’s a powerful space. If you’ve often felt excluded there is a symbolic power at being at the heart of one of the most important monuments in the world. You are invited in and it is yours. You are given the freedom to be there and muck about and play music and hug and love. Or just to watch the sun – it’s very potent.”

One of the participants, who asked not to be named, said: “Projects like Human Henge are very rare, which is such a shame, because they are very effective.” He said he had been in contact with mental health services for more than 30 years and it had allowed him to find lost confidence.

“From day one of the project there was an objective, a reason for being there. For others, and myself it was not about mental health or treatment, although it is important, it was about learning and getting private time in the stones.

“None of us knew that we would be forced to sing or walk for miles but these were some of the best fun we had.”