BOSTON — When Beth Homand applied a decade ago for mental health counseling for her son, who has Asperger’s syndrome, she was turned down.

Because her son’s primary diagnosis was autism, and his IQ level was higher than a minimum threshold of 70, Homand was told he didn’t qualify for state mental health services.

“This was a kid who was saying he wanted to kill himself,” said Homand of Falmouth. “He wasn’t able to function in school and was slipping behind. We couldn’t get help.”

It wasn’t until his late teens that Sam Homand, who recently turned 22, qualified for mental health services, his mother said, but that was only after years of battling state bureaucracy.

Homand isn’t alone. Hundreds of individuals with both autism spectrum disorders and mental health issues are falling through the cracks of public assistance, according to advocates who are pushing to plug the gaps.

A proposal being considered by lawmakers would require the Department of Mental Health to provide counseling and other services to those diagnosed with autism spectrum disorders, provided that they qualify for mental health assistance.

“Individuals who have both autism and mental health diagnoses often struggle to access the state services they need,” said Sen. Barbara L’Italien, D-Andover, the bill’s primary sponsor. “We cannot let these vulnerable people slip through the cracks.”

Lawmakers passed a major overhaul of health care regulations in 2014 aimed at improving improving public services for individuals with autism.

Signed by then-Gov. Deval Patrick, the legislation changed the eligibility for state services to include adults with autism, expanded MassHealth coverage for autistic patients under 21, and required agencies to develop plans for individuals who need both autism and mental health services.

Advocates say people with dual diagnoses still don’t get the help they need.

“There are far too many individuals who fall into the gap between the two agencies,” said Rita Gardner, president and CEO of Andover-based Melmark Inc., which works with the developmentally disabled.

Gardner supports L’Italien’s proposal, saying it would ensure people with both mental health issues and autism receive state services.

Recent studies have found that children and adults with autism spectrum disorder have a higher rate of attention deficit and hyperactivity disorder, depression, bipolar disorder, schizophrenia and other psychiatric disorders than the general population.

More than two-thirds of children with autism have been diagnosed with one or more psychiatric disorders, according to the National Institutes of Health.

Overall, the state has struggled to expand services for autism as the numbers of children diagnosed with the disorder has increased, advocates say.

Gov. Charlie Baker’s budget for the coming fiscal year boosts funding for the Turning 22 program to $21.4 million — an increase of $16.7 million. The program pays for housing, transportation and other services for young adults with disabilities who havee reached their 22nd birthday and are too old for day school and special-education programs.

Baker’s proposal is still being debated by House and Senate lawmakers.

Leo V. Sarkissian, executive director of The Arc of Massachusetts, which works with the developmentally disabled, said a spike in the number of children diagnosed with autism in recent years has flooded the system with more individuals seeking services.

“That’s put a lot of pressure on the system,” he said. “There are a lot of people on waiting lists for both developmental and mental health services.”

The needs for people with dual diagnoses run the gamut — from group homes to transportation to jobs at a company that hires people with developmental disabilities.

Families are challenged to figure out which federal or state agencies provide funding or services, not to mention qualifying for the support, advocates say.

Also, many mental health workers are not trained to deal with patients who also have autism spectrum disorders, advocates say, while clinicians who work with autistic patients generally aren’t trained to recognize symptoms of mental illness.

Homand, who said her son now has the support he needs, said she knows many families in the state are still caught in the middle — with no assistance.

“The state has figured out how to support people with other intellectual disabilities like Down syndrome by helping with housing, transportation and other needs,” she said. “But they’ve done a totally inadequate job of supporting people like my kid.”

Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites. Email him at cwade@cnhi.com