It's been found that nature, or being in a natural environment, can reduce fear and anxiety, help us relax and improve our sense of well-being.
Gardens, bushland and parks are increasingly being used to help those suffering from depression, substance abuse and anxiety.
One such nature-based program is The Outdoor Experience, which provides a range of programs for teenagers and young adults with drug or alcohol problems, including a 12-day journey through remote Victorian countryside, where a group of six or eight young people carry everything they need on their backs.
Facing the elements, cooking their own meals on a portable stove and sleeping close to the ground often generates huge changes in people's lives.
Terry Vella, a social worker who accompanies Weeks on the trips, said that conquering peaks and climbing cliffs makes the young people realize they can surmount life's other hurdles, too.
"It's all about being out there, being part of a natural process. One of the most powerful aspects of being in the wilderness is that it makes you re-examine your life," the Courier Mail quoted Vella, as saying.
Cathryn Carpenter, an education lecturer at Victoria University, has been working alongside Vella and Weeks in a bid to pinpoint what makes the natural environment such powerful therapy.
"The nature part is pretty essential. It's a source of inspiration, a place away from the usual chaos, the person is fully immersed in this new environment. You have to take on responsibility and engage with people. No-one else is going to cook your dinner or put your tent up for you," she said.
This type of "ecotherapy" is being championed by mental health organization Mind in the UK, which commissioned the University of Essex to investigate the health benefits of nature on a group of 20 people suffering from depression.
The study found that a walk in the country or a park made 94 per cent of respondents experience a decrease in their depression, while only 45 per cent felt better after walking in a shopping mall.