The figure is the Commission’s budget for the 2016-17 financial year, and represents an increase of $14.7 million on last year’s.
The $865.8 million is an 83.9 per cent funding increase since 2008-09.
Premier Colin Barnett said the move reflected a better understanding of mental illness.
“Despite constrained fiscal circumstances, we have prioritised areas of social need,” he said.
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READ NOWHe said the funding would help ensure crucial fixtures, like alcohol and drug counselling services and mental health treatment, continued to receive strong government support.
Mr Barnett made the announcement at the WA Council of Social Services State Conference.
There will be more mental health beds for youth at Perth Children’s Hospital and Fiona Stanley, doubling the number of such dedicated places since 2008.