This Employee Benefit Research Institute issue brief explores issued related to full mental health parity.

From the report:

When employers began to provide health insurance benefits to their employees and their families, they extended coverage to include mental health benefits under the same terms as other health care services. Many employers continued to add mental health benefits through the 1970s and early 1980s until cost pressures required employers to re-examine all health care benefits that were offered. They quickly found that, while only a small proportion of the beneficiaries used mental health care services, the costs associated with this care were very high. As a result, employers placed limits on mental health benefits in an attempt to make the insurance risk more manageable.

Full report: http://ebri.org/publications/ib/index.cfm?fa=ibDisp&content_id=92

Employee Benefit Research Institute. (1997). Issues in mental health care benefits: the costs of mental health parity.