A project team at the Institute of Psychiatry is gathering data on the number of people with specific mental disorders in England, the number treated and the care packages they typically receive.
The next stage will be to examine how much this will cost over 20 years and what might be gained from providing more appropriate, evidence-based services.
King's Fund senior fellow in mental health Simon Lawton-Smith said: 'It's looking at prevalence rates and trends and the way services are provided at the moment, and making assumptions about the future if we take different options and follow all the National Institute for Health and Clinical Excellence guidance.'
The review is expected to be published in October or November.
The steering group is chaired by Sir Derek Wanless, the former NatWest Group chief executive who has conducted two major healthcare reviews for the government.
Mr Lawton-Smith said: 'We will miss this year's comprehensive spending review but would hope to influence the following one.'