Participants suffered from a range of conditions including depression, bipolar, schizophrenia and post-traumatic stress disorder.
The project eventually gathered about 20 people who met weekly to discuss what it was that made them happy. It was so successful carloads were arriving from the mental health unit at Whangarei Hospital.
"It started off with people not being able to say what happiness was at all," Davie said. "When you teach yourself what makes you happy then you seek that out more."
The documentary, which was in the production stages, followed four of the participants through their journey, she said.
Some chose not to be filmed because of the stigma attached to mental illness. One of those who featured in the documentary was not a mental health patient but a physiologist of 36 years who took on the project to understand his patients better.
After the 100 days he had left his job because he realised it was no longer what made him happy.
The aim was to create a feature-length documentary which would go into film festivals nationally and overseas, Davie said.
The creators wanted to raise awareness with the potential for it to become a teaching tool for other mental health patients.
Like any project, it came at a cost, which they were struggling to cover.
Davie said she estimated $15,000 was needed to finish the documentary, which would hopefully happen by the end of the year.
A lot of that cost was for rights to use 60 seconds of the popular song Happy by Pharrell Williams.
Some people might think it was a bit indulgent, but the song fitted the documentary "perfectly", Davie said.
While the focus for the project was on people with mental illnesses, the underlying idea was something everyone could relate to, she said.
"Most people think they are happy or think they know what makes them happy, but when you get into it they are not doing it. That's mostly because life gets in the way."
-To donate, email: alidav@xtra.co.nz
