Last August, Cathy Costello watched in horror as her mentally ill son stabbed her husband to death in a restaurant parking lot.

She and her husband, Labor Commissioner Mark Costello, had struggled for eight years and spent more than $150,000 to get help for Christian Costello, who remains jailed on a count of first-degree murder.

That money came out of their pockets, because they struggled to get insurance to cover the expensive treatment for their son.

Now, she has joined Oklahoma Insurance Commissioner John Doak in a campaign to raise awareness about mental health coverage, and the appeals process available when claims are denied.

Doak told KRMG Friday that all insurance plans, by law, are required to cover mental health and substance abuse services, including inpatient treatment, therapy, and counseling.

It's estimated that one in four adults suffer some form of treatable mental disorder.

But there's a social stigma associated with mental health problems, and it's a topic most people are reluctant to discuss.

That often means they don't realize that help is available, Doak said.

"Consumers don't know that if they're denied coverage through the mental health process, through the diagnosis process, there is an appeal process," Doak said.

The first step is a direct appeal to the insurance company; the second is an external review and appeal, both of which involve the Oklahoma Insurance Department (OID).

"The third is more of a mediation process," Doak added.

Costello has become the public face of OID's informational campaign.

"This is a major issue," she told KRMG. "Not very long ago, a lot of insurance policies did not recognize mental illness as something that needed to be covered. Yet, it's an illness of the brain, it's a chemical imbalance, and the most important organ in your body is your brain. If your brain's not working, your body's not working."

She pointed out that mental illness affects not only the patient, but their family and the community as well.

And although she and her husband were willing to do anything they could to help their son, they didn't realize they could challenge their insurance providers when claims were denied.

"If I'd known about an appeals process, a mediation process, you can be sure I would have taken advantage of that," she told KRMG. "I think people don't know, they don't read their policies. Some times it's confusing, the language is thick, and they're afraid, or they don't even know that they can challenge it."

To read more about insurance coverage for mental illness, and the appeals process available to consumers, CLICK HERE.