Nearly 2 million adults in California — including more than 122,000 in the Sacramento region — need mental health treatment, but the majority receive inadequate services or none at all, despite a state law that requires health insurers to cover mental health care, a new study shows.

One in 12 Californians reported symptoms consistent with severe psychological distress and experienced difficulty functioning at home or work, according to a report by the UCLA Center for Health Policy and Research.

Over half of these adults reported receiving no treatment for their disorders and about a quarter received “inadequate” treatment, the study concludes.

Inadequate treatment is defined as less than four visits with a health professional over the preceding 12 months or using prescription drugs to manage mental health needs.

The study used data from the 2007 California Health Interview Survey conducted by the center, but situation doesn’t appear to have gotten better.

“There is a huge gap between needing help and getting help,” David Grant, the study’s lead author and center director, said in a news release. “The data also show large disparities in mental health status and treatment by demographic, economic and social factors. These findings can help direct the state’s limited resources to those in greatest need of help.”