Techniques used by mothers to soothe crying babies are helping the mentally ill stay calm without drugs or restraints.

Soft music, dimmed lighting and weighted blankets are among measures being used in "sensory intervention" trials at mental health units.

The project, developed by Te Pou, the National Centre for Mental Health Research, AUT University and Auckland District Health Board has seen four sensory rooms tested in Auckland, Counties Manukau, Palmerston North and Wellington.

Though not aimed at replacing medication, Te Pou programme leader Michael Wilson said staff were reporting lower use of optional drugs among patients.

The sensory approach is "more direct, quicker and more effective," he said.

Preliminary results from the trial will be available in March, but Wilson said the techniques were already being widely adopted.