The proposal also would clarify age restrictions on gun ownership, specifying that residents must be at least 21 years old to own a gun. According to O'Malley's office, there are conflicting provisions in Maryland law about age restrictions.

In an effort to limit gun access for people with mental illness and a history of violence, O'Malley proposed adding more health records to the database used for background checks. People who are civilly committed or deemed mentally incompetent by a judge could be more easily denied a gun.

The legislative package also sets aside $400,000 for the state police to automate its background check system for gun purchases and calls for adding 160 troopers to the 1,450-member force.

In addition, the governor provided details of his plan to strengthen the state's mental health system. They include encouraging early interventions for child and adolescent patients, bolstering the ability of police and crisis management teams to handle mental illness in the field, and improving the continuity of care for psychiatric patients as they move between clinical and community settings.

Dr. Joshua Sharfstein, the state's health secretary, said many proposals have the same theme: Finding ways to make mental health providers the first line of defense for crises now handled by police. Sharfstein said that the goal was to avoid policies that would scare psychiatric patients and make them less inclined to seek help.

Mental health advocates and psychiatrists in the state expressed support for many of the proposals, saying the state's mental health system needs a funding boost after years of diminishing budgets. Others expressed misgivings that the package appears to link mental illness with gun violence — a link they say is not backed by research.

"I'm just cringing," said Laura Cain, an attorney with the Maryland Disability Law Center. "There's already such a tremendous amount of stigma. … The risk is cementing that image, and you're never going to be able to undo that."

Baltimore Sun reporter Kevin Rector contributed to this article.