Using the self-help automated program to prevent depression could be likened to using sun cream to prevent skin cancer, chief investigator Professor Helen Christensen told AAP.
The study by the Black Dog Institute, the Australian National University, University of Sydney and the University of Virginia is published in the journal Lancet Psychiatry.
The study involved SHUTi, an online CBT-based insomnia intervention designed by the University of Virginia and commercially available.
The 1149 participants were internet users aged 18-64 with insomnia and depression symptoms, but who did not meet criteria for major depressive order.
They were randomly assigned to receive SHUTi or another online program containing information about general health.
The first group experienced significantly reduced insomnia, anxiety and depression, with these improvements persisting for at least six months.
“This is the first trial in the world to demonstrate that CBT-based insomnia treatment can also have a significant impact on the development of depression,” Prof Christensen said.
“Since insomnia treatment is rarely stigmatised, this will remove a significant hurdle for those people who feel uncomfortable seeking help.
“This program had the same level of effects expected of face-to-face treatment but was delivered by automated software, giving us a cost-effective way for us to quickly distribute quality treatment and prevention programs across large geographic areas and to a wide range of users.”