Research led by the University of Adelaide has revealed why lithium is effective on some bipolar patients and not others.

Patients with bipolar disorders who also carry genes linked to schizophrenia are less likely to respond to leading bipolar medication, a new study has found.

Researchers have discovered why the mood-stabilising drug lithium has only worked for about 30 per cent of patients suffering manic and depressive episodes.

An international consortium, led by a professor from the University of Adelaide, says the findings could affect the quality of life for people with the significant mental health condition.

"These findings represent a significant step forward for the field of translational psychiatry," the university's Professor Bernhard Baune said.

"This doesn't mean that the patient also has schizophrenia - but if a bipolar patient has a high gene load of schizophrenia risk genes, our research shows they are less likely to respond to mood stabilisers such as lithium."

Understanding the biological properties of the drug, which had the ability to decrease the risk of suicide, was vital, Prof Baune said.

"In conjunction with other biomarkers and clinical variables, our findings will help to advance the highly-needed ability to predict the response to treatment prior to an intervention," he said.

The research findings have been published on Thursday in the journal JAMA Psychiatry.