State laws that require private health plans to provide coverage for substance use disorders (SUD) that is equal to benefits for general medical coverage can increase access to SUD treatment, a new study suggests.

More than half of states have enacted these laws, known as parity laws. The Emory University researchers analyzed state-level SUD parity laws in the private insurance market that were implemented between 2000 and 2008. They found parity laws increased state-level treatment by 9 percent in all specialty SUD treatment facilities, and 15 percent in facilities that accept private insurance.

The study appears in JAMA Psychiatry.

The passage of the 2008 Mental Health Parity and Addiction Equity Act and the 2010 Affordable Care Act incorporated SUD parity into federal legislation, HealthCanal reports. “This research suggests that the recent federal parity legislation holds promise for improving access to SUD treatment in this country,” said lead researcher Hefei Wen.